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DSB 13.10.15: Crash MH17, 17 July 2014

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Cross-sections were made using the FIB technique on fragments recovered from the
remains of the crew members, that had a glass and/or aluminium deposit. Scanning
electron microscope examinations of the cross-sections created showed that both the
aluminium and glass deposits were present in the form of thin layers of re-solidifed
material. These layers have a thickness ranging from tenths micrometres to tens of
micrometres (Figure 38). On a small number of fragments thin layers containing traces of
copper and plastic were found.
Figure 38: Example of SEM examination on a cross-section made using FIB. Note: 1) Layer of platina deposited
                by NFI, 2) layer of re-solidifed molten cockpit glass, 3) unalloyed steel. (Source NFI)

The elemental composition of the aluminium traces found were consistent with the
elemental composition of the aluminium obtained from the aeroplane as reference
material. The investigation did not analyse each trace of aluminium to identify which
aluminium alloys were present.
The glass deposits present on the surface of the 14 fragments had an elemental
composition of sodium, aluminium, silicon, oxygen and zirconium. This composition
corresponds to that of cockpit window glass from a reference piece held by the NFI and
with the cockpit glass obtained from the wreckage. The other pieces of glass that were
secured from the wreckage contained no zirconium. It is noted that common types of
glass, such as window glass, car windscreen glass and glass on mobile telephones do not
contain zirconium.
The examination further showed that several fragments recovered from the crew
members (Figure 39) were heavily deformed on one side of the fragment and that the
opposite side was only slightly deformed. The deposits that were detected were mainly
found on the heavily deformed side of the fragments in a re-solidifed state.


Figure 39: Micro CT-images of the fragments (shown at the right side of Figure 37, left from the First Offcers
               and right from the Captains body) show the deformation of the fragments. (Source: NFI)

The investigation concluded that these fragments impacted the aeroplane at a very high
velocity, thereby deforming the object at the side of the impact. The consequential
frictional heat melted the aeroplanes materials (glass, aluminium etc.) and a thin layer of
solidifed aeroplane material was deposited to the heavily deformed side of the object.
Although the velocity of the object was reduced due to the impact with the aeroplane,
the object continued its path and then impacted the crew member where it was found.
These fragments were as such assessed to be high-energy objects.
The chemical composition of 20 selected fragments which had either a very distinctive
shape (including the two bow-tie shaped pre-formed fragments) or a layer of deposits or
both was determined. This was determined by means of laser-ablation inductively
coupled plasma mass spectrometry.
A comparison between the fragments and their composition was made using a statistical
analysis method called Principal Component Analysis. The analysis showed that the
20 selected fragments from the wreckage and the remains can be divided in two
distinctive groups. Within such a group, no statistical difference could be determined
between the fragments, indicating that the fragments originated from the same source.
In other words, the fragments within a group were made from the same unalloyed steel
base material (i.e. the same plate). One of the analysed fragments could not be linked to
a distinctive group.
The result of the Principal Component Analysis was that from the 20 selected fragments,
19 fragments were assessed to be high-energy objects; 8 originated from the flight crew
and 11 from the wreckage. A summary of the results is given in Table 11 and Table 12.
One fragment not linked to either of the two distinctive groups above was concluded to
be a high-energy object as well. This conclusion was drawn primarily on the basis of the
fragments shape (a deformed cubic form) and the presence of a similar glass deposit on
the fragment.



The examinations showed that one further fragment, not included in the Table 11, that
was obtained from a passenger was found to be coal slag.
Number  Location                  Shape and dimensions    Mass       Group (see below)
                                                  (millimetres)          (grams)
1           Document binder                  -                           -                  2
2           Document binder                  -                           -                  2
3           Cockpit                         Irregular,                    4.9                 1
4           Cockpit                         Irregular,                    1.3                 1
5           Cockpit                         Irregular,                    2.5                 1
6           Cockpit                         Irregular,                    1.1                 2
7           Wreckage                     Irregular,                     3.2                 2
8           Wreckage                     Irregular, -                   2.7                 1
9           Wreckage                     Irregular, -                   0.8                 1
10         Cockpit                         Bow-tie, 14 x 14 x 4.5  6.1                 1
11         Cockpit                         Irregular, -                   2.7                 1
12         Human remains             Irregular, -                   3.5                1
13         Human remains             Irregular, -                   0.1                1
14         Human remains             Irregular, -                   0.1                1
15         Human remains             Cubic, 6 x 6 x 5            1.3                Other
16         Human remains             Irregular, -                   1.5                1
17         Human remains             Irregular, -                   2.2                1
18         Human remains             Irregular, -                 16                   2
19         Human remains             Cubic, 12 x 12 x 1        1.2                2
20         Human remains             Bow-tie, 12 x 12 x 5     5.7                1
Table 11: Overview of the 20 selected fragments.

The elemental composition of the two groups in the column of Table 11 is shown in
Table 12.


Table 12: Composition in (percentage) of elements found in steel of the two groups of fragments examined.

2.16.3 Explosive residue and paint analysis
In addition to the examination described above, as part of the criminal investigation,
126 swab samples were taken on various locations of the wreckage of the aeroplane and
one of the missile parts in paragraph and analysed by the NFI for the presence
of explosive residues.
Approximately 30 of the 126 swab samples showed traces of mainly two different
explosives; the nitroamine RDX and trinitrotoluene (TNT). A few of the 30 samples
showed traces of PETN. On the tested missile part traces of RDX was found. On the
missile part TNT or PETN could not be identifed.
The investigation into the origin of the explosive residues was made more complicated
as the objects from which the swab samples were taken had been exposed to the
elements for a long period of time. The possibility of contamination during transport and
by the fact that the wreckage lay in an area of armed conflict is a concern for the explosive
residue analysis.
One of the fragments that was recovered from the wreckage of the aeroplane, was found
in the left wing tip and a second one was found lodged in the left cockpit window frame.
Figure 40 shows images of both of these fragments.


Metal fragment recovered from inside the left wing                   Location of the fragment inside the left wing tip,
tip. (Source: Dutch Safety Board/Dutch National Police)             seen from below. (Source: Dutch Safety Board)
Metal fragment recovered from the left cockpit                         Location of the fragment in the left cockpit
window frame. (Source: Dutch Safety Board)                           window frame. (Source: Dutch Safety Board)
Dutch National Police)
Figure 40: Two of the metal fragments recovered from the aeroplane wreckage.

A number of paint samples taken from these metal fragments recovered from the
aeroplane and missile parts recovered at the wreckage area (see Figure 36 and Figure 40
and in paragraph were compared.
The colour and build-up of the paint layers was visually examined and the chemical
composition of the paints were analysed using Fourier-transform infra-red spectrometry.
The missile parts found at the wreckage area and the fragments recovered from the
wreckage were painted with the same number of paint layers and had the same colour.
Furthermore, the chemical composition (as analysed using Fourier-transform infrared



spectroscopy) of each paint layer was identical for the samples analysed. It was concluded
that the paint samples taken from missile parts could not be distinguished from those
found on foreign objects extracted from the aeroplane.
The results of these analyses were provided to the Dutch Safety Board by the public

Summary of forensic investigation
Over 500 fragments were recovered from the wreckage of the aeroplane, the
remains of the crew members and passengers. Many of the objects were
identifed as personal belongings, aeroplane parts or objects that originated
from the ground after impact. In addition, many of the objects were metal
fragments that were suspected to be high-energy objects, or parts of them.
From the second group of objects, 72 fragments that were similar in size, mass
and shape were further investigated.
43 of the 72 fragments were found to be made of unalloyed steel and four of
these fragments, although heavily deformed and damaged, had distinctive
shapes; cubic and in the form of a bow-tie.
On 20 of 43 fragments made of unalloyed steel, a thin layer of re-solidifed
aluminium and glass was detected. These fragments were found both in the
remains of crew members and in the cockpit area of the wreckage. No unalloyed
steel fragments were found in the remains of the passengers.
The elemental composition of the re-solidifed glass was compared with the cockpit
glass and was found to match. Likewise, the elemental composition of the aluminium
deposits matched the composition of the aluminium used in the aeroplane.
Deformation and abrasion of the fragments was caused by the impact of the
fragments with the aeroplane at very high velocity. The consequential frictional
heat resulted in the formation of a thin layer of re-solidifed aeroplane material on
the fragment. These fragments were as such assessed to be high-energy objects.
Some of the recovered aeroplane wreckage parts and one of the missile parts
recovered showed traces of explosive residues.
Paint samples taken from missile parts found in the wreckage area match those
found on foreign objects extracted from the aeroplane.

2.17 Organisational and management information

Factual information and the analysis related to the decision-making processes around
the flight routes are contained in Part B of this report entitled Flying over conflict zones.
The following subjects relevant to this crash were investigated:
The decision-making with regard to flight routes by Malaysia Airlines, with particular
emphasis on the route across Ukraine;



The management of airspace in Ukraine, with particular emphasis on the restrictions
of airspace promulgated by the Ukrainian authorities.

2.18 Additional information

This paragraph contains a number of relevant subjects that have not been addressed
elsewhere in Section 2. These relate to:
the pressure cabin and the cabin emergency oxygen system;
background information on possible external sources of damage to the wreckage
the safety actions taken following the crash.
2.18.1 Pressure cabin
Crashes in the past have shown that an in-flight break-up can occur following the sudden
failure of a pressurised cabin. Therefore, information relating to the functioning of the
pressure cabin were reviewed. Malaysia Airlines provided a list of mandatory occurrence
reports for the aeroplane that was involved in the crash, reflecting the period between
delivery in 1997 and November 2013, none of which related to the functioning of the
pressure cabin.
Maintenance information from Malaysia Airlines for the period between November 2013
and 17 July 2014 did not reveal any tail strike occurrences or damage to the rear bulkhead.
A review of the entries in the aeroplane technical log (ATL) in the period from November
2013 to July 2014 showed write-ups of buzzing or whistling noises emanating from the
seal of two cockpit windows and one cabin door. Repairs to the seals had been made
and annotated in the log.
Technical information provided by Malaysian Airlines indicated that repairs to the
fuselage skin in Section 46 had been carried out in 2012 and 2013 due to corrosion. The
repaired fuselage skin panel was recovered with all of the repair still in place.
A Service Bulletin had been issued by Boeing (reference number 777-53A0068) to
address the risk of a fuselage skin rupture in the SATCOM antennae area which could
result in a depressurisation of the cabin. The Service Bulletin was made mandatory by
the Federal Aviation Administration who issued Airworthiness Directive 2014-05-03. The
Service Bulletin was not applicable to the aeroplane that crashed. This issue is explained
in more detail in paragraph 3.2.2.
2.18.2 Emergency oxygen system description
Emergency oxygen for the flight crew is stored in oxygen bottles installed below the
cockpit. Oxygen is supplied as soon as the flight crew don their masks, irrespective of
the cabin pressure. Entries in the ATL made by ground engineers from Malaysia Airlines
showed that the oxygen bottles had been replenished on a regular basis in accordance
with standard maintenance practices.



The Boeing 777 is equipped with a cabin emergency oxygen system consisting of
chemical oxygen generators with masks that are stored above the seats. Each passenger
seat, cabin attendant seat, toilet and crew rest berth have masks, including additional
masks for infants travelling in the lap of an adult passenger.
The emergency oxygen masks can be deployed manually by pushing the PASS OXYGEN
switch in the cockpit on the pilots overhead panel. The masks will be deployed
automatically, when the cabin pressure altitude exceeds 13,500 feet. In the event of a
sudden loss of pressurisation, e.g. a depressurisation, the masks will deploy according to
the aeroplane manufacturer, with a time delay of a few seconds. Sometimes masks
deploy unintentionally, when the passenger service unit (PSU) is exposed to a heavy
shock or distortion of its container; for instance after a hard landing.
When the emergency oxygen masks are deployed, either manually or automatically,
internal software logic to the Electrical Load Management System will result in an activation
signal to open the passenger service units above each block of seats. The system logic has
an in-built delay for the activation signal. The signal activates the solenoid switch of the
passenger service units. The activated solenoid switch withdraws a latch pin in the door
panel of the passenger service unit, allowing it to open, followed by the masks falling out.
The chemical oxygen generators are fred by a downward force being applied to the
mask. The application of this force results in the attached lanyard pulling out the fring
pin, which in turn allows the mixing of chemicals in the generator. This mixing of chemicals
starts a chemical reaction that provides a high concentration of oxygen starting to flow
to the mask via a hose for about 10 to 20 minutes.
The aeroplane manufacturer stated that the Electric Load Management System nonvolatile memory does not record a signal as to whether or not the Electrical Load
Management System has activated the emergency passenger oxygen system, so as to
deploy the masks. The Flight Data Recorder does not record information regarding the
activation of the emergency oxygen system. However, in the event of activation this will
generate a Master Caution warning. The Master Caution warning and the cabin pressure
altitude are both recorded. The recorded cabin pressure altitude during cruise flight up
to the moment that the Flight Data Recorder stopped recording was 4,800 feet and there
were no warnings recorded.
According to the aeroplane manufacturer, the operator can choose whether or not to
store the signal that activates the emergency oxygen system on the Quick Access
Recorder (QAR), if installed. The aeroplane did have a QAR installed which was not
recovered from the wreckage site. Malaysia Airlines provided QAR data from earlier
flights to show that the failure of the pressurisation of the cabin pressure system and
cabin pressure altitude warning were recorded, but not the actual activation of the
emergency oxygen system.
During the investigation about ffty chemical oxygen generators were recovered from
the wreckage sites. With the exception of one, none of the chemical oxygen generators
had its fring pin in place and all displayed a black coloured stripe; an indication that the



generators had been fred. An example of one of the chemical oxygen generators found
and a part of its passenger service unit is shown in Figure 41
Figure 41: Chemical oxygen generators and part of the passenger service unit. (Source: Dutch Safety Board)

Some chemical oxygen generators were attached to their passenger service unit; others
were found separated. All of the chemical oxygen generators were damaged and most
of them were heavily distorted. About a dozen of the plastic PSU containers, or a part of
them, which normally contain the emergency oxygen masks, were found. The containers
are relatively rigid, but may nevertheless be deformed. The containers were heavily
damaged, incomplete or cracked. All the latches, which cover the masks and keep them
stored in the container, were missing. All of the solenoid switches were found in the
unlatched position. A few switches were damaged and could not be reset in the latched
position. For most of the chemical oxygen generators recovered, the masks and oxygen
supply tubes were missing.
The chemical oxygen generator which had a fring pin installed originated from a crew
rest area, which has a different stowage construction to the ones in the passenger service
units. The stripe on this chemical oxygen generator was orange/red, indicating that the
generator had not been fred. The latch was found separated from the plastic box and
the corresponding frame of the latch box was cracked. The solenoid switch was found in
the unlatched position and its lever was heavily distorted and could not be reset to the
latched condition. The two emergency oxygen masks and the oxygen supply tubes in
this unit were found intact


Figure 42: Emergency oxygen mask found on passenger. (Source: Dutch Safety Board)

During the victim identifcation process in the Netherlands, one passenger was found
with an emergency oxygen mask, see Figure 42. The strap was around the passengers
neck and the mask was around the throat. No information was available about how this
passenger was found at the wreckage site. The NFI examined the mask for biological
traces and performed DNA tests. No DNA profles could be obtained from the fve
samples taken. Therefore, DNA analysis was not possible. The lack of DNA material can
be explained by the mask having been left outside for a long time at high temperatures.
There were no useable fngerprints found on the mask. The high temperatures may have
caused the quality of fngerprints on the mask to deteriorate.



Summary of emergency oxygen system
The emergency oxygen masks can be deployed manually at any time by the
flight crew. During flight, the masks are deployed automatically, without an input
from the flight crew, when the cabin pressure altitude exceeds 13,500 feet.
The flow of oxygen through the mask starts when the fring pin is removed by the
application of a downward force on the lanyard attached to the fring pin and the
oxygen mask hose.
About ffty fred chemical oxygen generators were recovered. One, unfred,
chemical oxygen generator was found in a crew rest area.
A cabin pressure altitude of 4,800 feet was recorded on the Flight Data Recorder
during cruise flight up to the moment that the Flight Data Recorder stopped
There was no data recorded regarding the activation of the emergency oxygen
system on the Flight Data Recorder. The Quick Access Recorder, a potential
source of data, was not recovered.
One passenger was found with an oxygen mask. DNA analysis was not possible.

2.18.3 External sources of damage
In Section 3.5 a number of scenarios are analysed that relate to the possible source or
sources of the objects that perforated the aeroplane. These include meteor and space
debris. A number of military systems as possible sources of damage were also considered.
These are, for better readability, described in Section 3.6 of this report. This paragraph
provides factual background information on meteor strikes and the re-entry of space debris. Meteor
The investigation considered the possibility of a meteor as being the cause of the crash
and sought information from the Royal Dutch Society for Weather and Astronomy
(Koninklijke Nederlandse Vereniging voor Weer- en Sterrenkunde). The passage of a
meteor through the upper atmosphere (from 110 down to 15 km above the earths
surface) is associated with distinct, measurable sound waves as it decelerates to speed
below that of the speed of sound. These sound waves, at a frequency outside the range
of the human ear, are known as ultranoise.
The Royal Dutch Society for Weather and Astronomy confrmed that no such sound
waves were recorded in Ukraine at the time of the crash. In background information, the
Royal Dutch Society for Weather and Astronomy noted that meteors fall for the last
10-15 km in an almost vertical path, meaning that any such impact would be directly from
above, perpendicular to an assumed flat ground surface.
The chance of a meteor striking an aeroplane was calculated as being one event in 59,000
to 77,000 years. This value was obtained from the University of Pittsburghs Department of
Geology and Planetary Science and was originally part of the NTSBs investigation into the
1996 accident to TWA flight 800 (see NTSB Report AAR-00/03, dated 23 August 2000)


.101 Space debris
The Aerospace Corporation, a research and development centre based in the United
States of America that works with space programmes, maintains a register of the re-entry
of space debris. This register stated that no space debris re-entered the earths
atmosphere in the period 10 to 19 July 2014.

Summary of meteor and space debris information
The chance of a meteor striking an aeroplane was calculated as being one event
in 59,000 to 77,000 years.
No ultranoise was recorded in Ukraine at the time of the crash.
No re-entering space debris was known that could have hit the aeroplane.

2.18.4 Safety actions taken
Following the crash, at 15.00 (17.00 CET) on 17 July 2014 the UkSATSE issued NOTAM
A1507/14. This NOTAM added another restricted area above the existing area,
commencing at FL320 to an unlimited altitude.
At 23.00 on 17 July 2014 (01.00 CET, 18 July), UkSATSE issued NOTAM A1517/14, which
increased the size of the restricted area and imposed a limitation from the surface to an
unlimited altitude. This NOTAM became effective at 00.05 (02.05 CET) on the morning of
18 July. Table 13 summarises these NOTAMs. These two NOTAMs, issued by UkSATSE
and covering an area of the eastern part of Ukraine, closed the airspace.
NOTAM number             Lower limit             Upper limit               Valid from (UTC)
1507/14                         FL320                         UNL                    17 July, 15.00
1517/14                           SFC                          UNL                    18 July, 00.05
Table 13: Ukrainian NOTAMs post-crash.

2.19 Useful or effective investigation techniques

ICAO Annex 13 reserves a paragraph for providing information on useful or effective
investigation techniques that may be of use in future air accident investigations.
2.19.1 Wreckage registration and tagging
During the on-site recovery missions in Ukraine, wreckage parts were tagged, photographed
and registered. During the transportation to the Netherlands, this process was checked at
the different locations where parts were transferred to other means of transportation.
Upon arrival at Gilze-Rijen Air Force Base the wreckage was visually inspected, pieces of
wreckage were given a tag with an identifcation number and were then photographed
in front of a green screen. A database was created containing the following details for
each tagged piece of wreckage:



the identifcation of the part found;
its location in the aeroplane;
the location where it was found in Ukraine;
all the images made of that part or piece.
The Dutch Safety Board collected and maintained an archive of photos and videos of the
wreckage and the wreckage sites that were taken from 17 July 2014 onwards by
investigators, media and police. The photographic and flm material was used in the
database for wreckage registration. The information was valuable in noting whether
wreckage had remained undisturbed at the crash site or had been moved or taken away.
This information also assisted in the planning of the wreckage recovery missions.
2.19.2 Wreckage identifcation
The location of parts of the aeroplane was based on the appearance of the part, any
special features noted, station and stringer numbers on the parts. The fracture pattern of
the fuselage skin and its frame was drawn on a two-dimensional grid of stations and
stringer numbers. From these drawings it was possible to see whether parts were
adjacent or whether parts were missing.
The images of the parts were placed on a two-dimensional grid of station and stringer
numbers to make a digital two-dimensional reconstruction of the aeroplane. The photos
were also used to mark the mode of deformation of each fracture surface. For the
fractures analysed, the direction of the fracture and the direction of the principal stress
were determined when possible. The nature of a fracture was determined based on the
features of static overloading, fatigue and corrosion. For static overloading, the major
deformations or fractures observed were linked to the type of overloading, i.e. pure
tensile, tensile-shear, tensile-bending or tear. Together with the examination of the
fractures, deformation of all parts was studied, both the in and out of plane deformations.
These deformations aided in interpreting the major load components leading to each
The major fractures were determined from the two-dimensional drawings and photo
reconstruction. The location on the ground where these parts were found was also
indicated on the digital two-dimensional photo reconstruction. Finally, all information
was combined to gain an insight of the break-up.
2.19.3 Wreckage reconstruction
The reconstruction of the aeroplanes fuselage and parts of the cockpit assisted the
investigation and allowed the Dutch Safety Board to demonstrate the results of the
investigation. The reconstruction was intended to demonstrate the answers to the
following questions:



From which position relative to the aeroplane did the high-energy objects come?
What were the effects of the impact of the high-energy objects on the aeroplane
How did the aeroplane break up?
The physical evidence of the recovered wreckage and other investigation activities were
suffcient for the Dutch Safety Board to complete the investigation. The reconstruction was
of signifcant value to the investigation as it allowed the investigators to better visualise the
recovered wreckage and the damage when comparing the analyses performed with the
parts of the wreckage. The assembly of the wreckage into a three-dimensional reconstruction provides the relatives of the passengers and crew, the stakeholders and the
public with compelling physical evidence of some of the main conclusions drawn in the
2.19.4 High-energy object analysis
Four studies regarding the source of the high-energy objects and the damage they
caused were produced by specialist external laboratories as part of the investigation.
The Dutch Safety Board requested specialist assistance from the Dutch National
Aerospace Laboratory (NLR) and the Netherlands Organisation for Applied Scientifc
Research (TNO).
The NLR work was performed by the Defence Systems Department. This department
provides operational, technical and scientifc support to the Dutch Ministry of Defence in
general, and the Royal Netherlands Air Force in particular. The main research subject is
airborne self-protection, which requires an extensive knowledge of the performance of
surface-to-air and air-to-air weapon systems. For this purpose the department has several
tools at its disposal. One of these is the Weapon Engagement Simulation Tool (WEST),
an in-house developed software tool to simulate the flyout and performance of threat
systems. The work was performed using pieces of wreckage at the Gilze-Rijen Air Force
Base, photographs and three-dimensional laser scans of some of the parts of the
aeroplane. The NLR report is contained in Appendix X.
TNO used a computer-based ballistic simulation to reconstruct the damage from an
assumed warhead when striking the aeroplane. This TNO report is contained in Appendix Y.
TNO performed a blast damage simulation using a computer model of the warhead. A
Computational Fluid Dynamics simulation was performed to provide a high fdelity,
quantitative, description of the blast loading that would be caused by the detonation of
the warhead identifed by NLR and TNO taken into account the evidence found. This
TNO report is contained in Appendix Z.
The details of how the software models for each company performs its calculations are
proprietary information to those companies and have, as such, not further been




3.1 Introduction

In this section, the signifcance of the relevant facts and the circumstances surrounding
the crash are analysed. In Section 2.12, it was established that the wreckage of flight
MH17 was spread out over a large area, indicating an in-flight break-up. In addition, the
break-up occurred after an abrupt loss of electrical power. In this analysis six main
subjects are distinguished:
1. General matters, including the flight crews qualifcations and the airworthiness of the
2. The flight before the in-flight break-up, including pre-flight planning, weather
considerations and flight operations;
3. The moment of the in-flight break-up;
4. The in-flight break-up, its aftermath and causes:
a damage analysis of the wreckage, with emphasis on the perforation of the
the source of the high-energy objects that perforated the aeroplane;
failure analysis of the aeroplane structure, and
passenger oxygen system.
5. Survival aspects, and
6. The recording of radar surveillance data.
These subjects are chronologically presented with specifc attention to the loss of
electrical power, the break-up and their causes. A number of different scenarios and
possible causes are considered and analysed.

3.2 General

3.2.1 Flight crew qualifcations
Based on the information in Section 2.5, the flight crew members were in possession of
valid licences and medical certifcates.

The flight crew members were in possession of valid licences and medical certifcates.



3.2.2 Airworthiness General
In order to establish the airworthiness of the aeroplane prior to the flight on 17 July 2014,
the investigation reviewed the way that Malaysia Airlines planned, performed and
documented the maintenance of the aeroplane. For example, Malaysia Airlines documented
system for the evaluation, deferral and later rectifcation of technical defects of the
aeroplane was examined. In addition, a list containing occurrence reports for the subject
aeroplane from the aeroplanes delivery in 1997 to November 2013 was reviewed. The
background to the material in this paragraph is contained in Appendix J. Two specifc
matters were analysed with regard to the crash. These relate to the aeroplanes pressure
cabin and to the engines. Pressure cabin
None of the mandatory occurrence reports for the aeroplane involved in the crash sent
to the Department of Civil Aviation Malaysia between aeroplanes delivery in 1997 and
November 2013 were related to the functioning of the pressure cabin.
Aeroplane technical log entries revealed that since the heavy maintenance check in
November 2013 cabin doors and a cockpit window produced buzzing or hissing sounds.
These type of complaints, which occasionally occur with jet aeroplanes, were caused by
leaking seals and were repaired. As such, these sounds may bring some discomfort for
passengers and crew, but would not cause a depressurisation. According to the aeroplane
technical log, no such complaints were present on leaving Amsterdam for the return
flight to Kuala Lumpur.
The Flight Data Recorder indicated that until the end of recording the cabin pressure
altitude was constant at 4,800 feet and correct for the cruise level at that time and no
warnings were recorded. Analysis of the passenger oxygen system is contained in
Section 3.12.
The aeroplanes rear pressure bulkhead and adjacent parts of the fuselage were not
found at the beginning of the debris pattern (sites 1, 2 and 3) but in site 4 (see paragraph This indicated that the failure of the rear pressure bulkhead was of a secondary,
rather than a primary failure. The fractures were predominately consistent with tensile
overstress indicating an instant overload resulting in a failure of the rear bulkhead
structure rather than, for example, a failure due to a faulty repair, fatigue or corrosion
(see paragraph 3.11.5 for more information on the rear pressure bulkhead).
Maintenance information and occurrence data from Malaysia Airlines was reviewed back
to the aeroplanes delivery in 1997. This data did not reveal any tail strike occurrences or
damage to the bulkhead. In addition, the physical evidence derived from the investigation
in the Netherlands allows the Dutch Safety Board to conclude that the rear pressure
bulkhead was not damaged prior to the flight on 17 July 2014.
In paragraph 2.18.1, the contents of Boeing Service Bulletin 777-53A0068 and
Airworthiness Directive 2014-05-03 were described. These documents addressed the
risk of a fuselage skin rupture due to corrosion under those SATCOM antennae installed



on top of the fuselage. This could result in depressurisation. The upper fuselage skin
area mentioned in the Service Bulletin was not recovered. However, Boeing and Malaysia
Airlines documentation revealed that the SATCOM antennae on the aeroplane that
crashed were installed above the rear passenger doors. This is a different location than
the 777 aeroplanes addressed in the Boeing Service Bulletin. Therefore, neither Boeing
Service Bulletin 777-53A0068 nor Airworthiness Directive 2014-05-03 were applicable to
the aeroplane that crashed.
According to Malaysia Airlines documents, a part of the fuselage at section 46 had been
repaired. This part of the fuselage was recovered and examined. The repair to the
fuselage skin was still in place and intact.
The aeroplanes structural integrity is further analysed in paragraphs 3.11.2 to 3.11.5. Engines
Information regarding engine maintenance carried out for the past three years by the
operator was received. It was not possible to determine whether complaints - if any - were
relevant to the investigation. However, aeroplane technical log entries since the last
major maintenance check in November 2013 did not show signifcant engine anomalies.
On 17 July 2014, the aeroplane technical log contained no complaints about the engines.
In addition, none of the occurrence reports referred to in paragraph were related
to the functioning of the engines.
The minor damage to the acoustic liners in the engine that was noted in the technical log
from time to time was considered to be consistent with normal wear and tear of the
engine. Such damage did not pose any hazard to the engines.
An analysis of Rolls-Royces Engine Health Monitoring data (see Appendix J) concluded
that no engine operating parameter limits were exceeded during the period between 4
and 17 July 2014. It can be concluded for both engines that there is no evidence of either
engine having encountered a failure or having shown unusual engine behaviour prior to
the departure from Schiphol on 17 July.

The Dutch Safety Board found no evidence to suggest that the aeroplane was not in
an airworthy condition on departure from Amsterdam Airport Schiphol. There were
no known technical malfunctions that could affect the safety of the flight.

3.3 The flight before the in-flight break-up

3.3.1 Pre-flight planning
Flight Data Recorder data from this flight and several previous flights, were reviewed in
order to determine the operators fuel calculation policy. The data indicated that the
flights landed with fnal reserve fuel (30 minutes flight time), diversion fuel and 20 minutes



contingency fuel. This represented a fuel value of between about 8,000 kg and 10,000 kg.
For flight MH17 the planned fuel remaining was 8,800 kg.
Based on Section 2.6, the aeroplanes mass and balance were within the required
manufacturers limits. There were no dangerous goods loaded as cargo.
An air traffc control flight plan was fled and the flight crew was provided with an
operational flight plan, NOTAMs, loading and weather information.
There were no technical defects noted on the aeroplane technical log that would have
affected the safety of the flight.
Based on paragraph 2.9.3, the planning of the flight route through Ukraine included the
flight across the Dnipropetrovsk Flight Information Region at FL330 - FL350. For this part
of the route there were no restrictions for these altitudes.

The pre-flight planning was conducted according to the applicable procedures.
The mass and balance of the aeroplane were within authorised limits.
There were no airspace restrictions affecting the planned route.

3.3.2 Flight execution Vertical profle
As stated in Section 2.1 of this report, the airlines operational flight plan called for a
climb from FL330 to FL350 at a point 74 NM before PEKIT, whilst the air traffc control
flight plan called for the climb to be made at PEKIT. This apparent discrepancy is the
result of the fact that the air traffc control flight plan is prepared earlier than the
operational flight plan and that the latter document takes account of a more recent
forecast for wind speed and direction. The operational flight plan is therefore more
accurate than the air traffc control flight plan as it contains recent weather information.
However, 6 NM before PEKIT, the captain decided to deviate from the planned vertical
profle by not climbing to FL350 as requested by the air traffc controller but maintained
FL330. It is not known why the flight crew did not accept this request as the flight crew
did not provide the air traffc controller with an explanation. The air traffc controller did
not request an explanation either.
The Dutch Safety Board tried to fnd an explanation for this operational decision by
discussing the operators procedures with Malaysia Airlines. Malaysia Airlines showed
that, as per the Boeing performance handbook, the optimal altitude to use for the
prevailing conditions was 33,800 feet at the time of the air traffc controllers request and
for the following 8 to 10 minutes. The optimal altitude in this case is related to fuel
effciency. As FL340 is a non-standard level for an eastbound flight (see paragraph 2.9.3),
the flight crew, in the opinion of Malaysia Airlines would have preferred to remain at



FL330. According to information provided by Malaysia Airlines, and included in the
operational flight plan, the weather forecast showed that the likelihood of turbulence was
less at FL330 than at FL350. Whilst neither factor can be confrmed as reflecting the flight
crews decision process, the Dutch Safety Board is of the opinion that the decision not to
climb from FL330 to FL350 was a normal operational decision made by the flight crew as
the result of normal operational considerations.

The flight crews decision not to accept the air traffc controllers request to climb
from FL330 to FL350 was determined to be a normal operational consideration. Horizontal profle
A comparison of the fuel consumption was made based on the last position report sent
by Aircraft Communications Addressing and Reporting System (ACARS) and the
operational flight plan. According to the operational flight plan, the aeroplane should
have passed air navigation waypoint PEKIT after 2 hours and 26 minutes flight time with
72,300 kg of fuel remaining. A position report transmitted by ACARS for a point 20 NM
past PEKIT showed that the aeroplane had flown 2 hours and 25 minutes and had
73,000 kg of fuel on board. 20 NM equates to about 2 or 3 minutes of flight and 40 kg of
fuel. The differences between the planned and the actual fuel consumption was
considered negligible. It was concluded that the flight proceeded as planned up to the
moment that the flight crew made a request to divert slightly to the north.
According to Section 2.7, the weather forecast for flight MH17 was similar to the actual
weather on 17 July 2014, as determined by aftercast. The weather was composed of
thunderstorms moving north from the Black Sea. Cloud cover varied between partial and
overcast over the eastern part of Ukraine. The weather was consistent with thunderstorms
that a flight crew would reasonably be expected to circumnavigate.
According to the information in paragraph 2.9.6, shortly after 13.00 (15.00 CET), the flight
crew requested a slight deviation around bad weather and received permission from
Dnipro Radar to deviate from the planned flight route. The aeroplane turned left to the
north-east. When approximately 6.5 NM north of the centreline of the airway L980 and
abeam air navigation waypoint TAGAN, the flight continued parallel to the L980 airway in
order to avoid the bad weather. In view of the forecast and actual weather, the flight
crews request and flight execution to deviate slightly to the north of the planned track to
avoid bad weather were considered consistent with normal operations. The higher and
more energetic clouds were south of the route, moving north-east. After circumnavigating
the bad weather, the flight turned slightly back to the right to approach the original route.
At 13.19:56 (15.19:56 CET) the flight crew acknowledged to Dnipro Radar the clearance to
proceed direct to waypoint RND.
At 13.20:00 (15.20:00 CET) Dnipro Radar advised flight MH17 to expect a further
clearance to proceed direct to TIKNA after RND. The information was not read back or
acknowledged by the flight crew. At this point in time, the aeroplane was within 5 NM of



the centreline of airway L980 and proceeding on a direct track to waypoint RND. The fact
that the flight crew requested a deviation of 20 NM but only flew approximately 6.5 NM
north, was consistent with normal operational practice of minimising any additional
distance flown.
The actions of the air traffc controllers are consistent with normal operations. The
communication between the flight crew and the air traffc controllers by both parties
appeared normal and was considered consistent with normal operations.

With the exception of a deviation requested by the flight crew to avoid bad weather,
the aeroplane followed the planned route, airway L980 across Ukraine. The maximum
deviation from the airways centreline was approximately 6.5 NM. This is considered
normal. Flight data
The Flight Data Recorder records approximately 1,300 parameters; for an effective
investigation a shortlist of parameters considered to be useful for the investigation was
created in order to gain an insight into the possible cause or causes of the crash. Relevant
details of the last three minutes of flight recorded on the Flight Data Recorder are
published in Appendix H.
The investigation included a verifcation that the aeroplanes warning systems had
functioned correctly and these signals were present on the Flight Data Recorder
recording. For example, the Flight Data Recorder contained a recording of the activation
of the aeroplanes master warning; a warning that should, and was, generated when the
autopilot was disconnected at a point on an earlier flight.
No aeroplane system warnings or cautions for flight MH17 were recorded on the Flight
Data Recorder. All engine parameters were normal for cruise flight until the recorders
ended at 13.20:03 (15.20:03 CET).
Flight Data Recorder engine parameters were continuously sampled during the flight.
According to the data on the Flight Data Recorder, both engines were running at cruise
power during the flight across Ukraine. All indications regarding the operation of the
engines were normal and no abnormalities were shown. All of the engine indications
were as they would be expected to be during cruise flight. No abnormal vibrations were
recorded. There were no warnings recorded. Appendix H contains an overview of the
engine data recorded on the Flight Data Recorder



The Flight Data Recorder contained data for flight MH17. No warnings were
detected for either aeroplane systems or for the engines in the analysis of the
Flight Data Recorder data for the flight on 17 July 2014.
According to the data, up to 13.20:03 (15.20:03 CET), flight operations were
normal. Flight crew
Analysis of the Flight Data Recorder and the Cockpit Voice Recorder did not reveal any
indications in the flight crews performance that suggested diminished capabilities or
incorrect actions.
Based on the results of the toxicological examination conducted, any contribution of
ethanol (alcohol), drugs, medicines and/or pesticides to the behaviour and/or the flying
skills of the First Offcer cannot be concluded and his death cannot be explained on the
basis of the results from the toxicological examination.
It was concluded that the flight crew handled the aeroplane appropriately.

The flight crew handled the aeroplane appropriately.
There is no evidence that the crew handled the aeroplane inappropriately or the
First Offcers flying skills were affected by alcohol, drugs or medicine.

3.4 The moment of the in-flight break-up

This Section is intended to establish and verify the moment at which the in-flight break-up
3.4.1 Aeroplane data recorders
According to the information in Section 2.11, the following Flight Data Recorder
parameters as recorded at 13.20:03 (15.20:03 CET) were as shown in the box below:



Aeroplane position
Latitude                                                    48.12715 N
Longitude                                                 38.52630538 E
Altitude *18                                           32,998 feet
Indicated airspeed                                       293 knots
Magnetic heading                                        115 degrees
Drift angle                                                     -4 degrees
Wind direction                                             219 degrees
Wind speed                                                   36 knots
Static air temperature                                   -44 ºC
Total air temperature                               -12/-13 ºC
Small variations in the data are possible due to differences in resolution from the various
data sources.
The latitude and longitude data is shown above in the format that it was recorded in. This
position is converted to read 48 07 37.74N 038 31 34.698E.
A detailed analysis of the Cockpit Voice Recorder, covering the last 20 milliseconds of
the recording at 13.20:03 (15.20:03 CET) as described in paragraph 2.11.2, was performed.
The analysis showed that two peaks of sound were identifed in this timeframe. Using
specialised audio recording analysis software, a graphical representation of the sound
over time, its waveform, could be established. The waveform analysis assisted in
determining the signals characteristics, for example, duration and energy.
The frst sound peak had a duration of 2.1 milliseconds and the signal was recorded on
the cockpit area microphone channel only. Because no other Cockpit Voice Recorder
channels recorded the frst sound peak, the direction of this signal could not be
established. Wave spectrum analysis suggested that the sound peak was representative
for an electrical spike as it showed the form of an electro-magnetic pulse that could
have been caused by static discharge or similar.
Signal triangulation was used to determine the origin of the second sound peak recorded
on the Cockpit Voice Recorder. The poor sound quality on the cockpit area microphone
channel noted during the investigation was most likely due to the missing microphone
cap from the cockpit area microphone. The fact that the microphone cap was missing
was noted on the aeroplanes deferred defects list.
*18 Altimeter set to the standard pressure of 1013.25 hPa



The time difference between the frst and the second sound peak was determined to be
2.3 milliseconds. The second peak had a duration of 2.3 milliseconds and was recorded
by all four channels. However, the recordings of the second peak were not simultaneous
on all channels; some of the recordings had a different timestamp. The wave spectrum is
representative for a sound wave. The time difference between the channels showed that
the sound was recorded by the cockpit area microphone (CAM) and pilot 1 (P1)
microphones frst, followed by the pilot 2 (P2) microphone and, lastly, the observer (OBS)
microphone. This difference in time showed that the sound wave originated outside the
aeroplane starting from a position above the left hand side of the cockpit, propagating
from front to aft (see Figure 43). It is concluded that the event was highly energetic in
nature based on the short time duration of the event.
Figure 43: Second sound peak - graphic representation. (Source: Dutch Safety Board)

Cockpit, from above
Cockpit, Cross-section (looking back)
Not to scale

The fact that the microphone cap of the cockpit area microphone was missing did not
influence the calculation. However, during the investigation, the Dutch Safety Board
noted that the sound peaks were of such short time duration that any minor differences
in recording will cause the signal triangulation to be erroneous. For example, signal
latency (refers to a short period of delay between when an audio signal enters and when
it emerges from a system) can be influenced by the Cockpit Voice Recorder microphone
wiring. When one microphone wire is longer compared to others this may affect the
time for the signal to reach the Cockpit Voice Recorder. Nonetheless, the signal
triangulation is consistent with the impact damage on the left side of the cockpit.
Therefore it is likely that the origin of the sound peak recorded on the Cockpit Voice
Recorder is a high frequency sound wave from outside the cockpit.
The Flight Data Recorder data as described in paragraph 2.11.3 and Appendix H was
examined to try and identify any acceleration or deceleration associated with the sound
wave that had been recorded on the Cockpit Voice Recorder. The following three axes of
acceleration with their sampling rate were recorded on the Flight Data Recorder:
longitudinal acceleration: 4 times a second (4 Hz);
vertical acceleration: 8 times a second (8 Hz);
lateral acceleration: 4 times a second (4 Hz)



The acceleration data on these three axes was examined and all three axes showed
stable data up to the recordings end at 13.20:03 (15.20:03 CET).

The Cockpit Voice Recorder audio ended abruptly. The short noise peak recorded
in the last 20 milliseconds of the recording was a highly energetic sound wave.
Signal triangulation showed that the noise originated from outside the aeroplane,
starting from a position above the left hand side of the cockpit, propagating from
front to aft.
The sound wave detected in the last 20 milliseconds of the Cockpit Voice
Recorder recording could not be observed in the form of acceleration data on
the Flight Data Recorder.

3.4.2 Surveillance radar data
The radar data that was received from Ukraine from UkSATSE showing flight MH17, is
described in paragraph From the Ukrainian raw radar data it was established that
the last secondary surveillance radar return was at 13.20:03 (15.20:03 CET) with the
aeroplane flying straight and level at FL330. The video radar replay did not show any
radar targets in the vicinity of flight MH17 at that time other than the three commercial
aeroplanes mentioned in paragraph
The surveillance radar data showing flight MH17, that was received from the Russian
Federation were from GKOVD, is also described in paragraph Flight MH17s
target was detected by primary surveillance and secondary surveillance radar. A second
primary target was generated close to the target labelled MH17 on two occasions. No
other data was received. Due to the absence of raw data, it was not possible to verify the
video radar replay. The video of the radar screen did not show any failures, emergency
codes or other alerts of flight MH17.
The Ukrainian radar data, comprising of both raw and processed data as described in
paragraph was analysed separately. The last radar data recorded by UkSATSE
showing no abnormalities with the target or symbol for flight MH17, was at 13.20:00
(15.20:00 CET). Time 13.20:03 (15.20:03 CET) coincided with two data points in the raw
data from secondary radar information provided by UkSATSE. The last position message
from the aeroplanes Automatic Dependent Surveillance - Broadcast data and the last
secondary radar target identifcation message both have a time stamp of 13.20:03 (15.20:03
CET). The processed data showed that no secondary surveillance data was displayed from
13.20:18 (15.20:18 CET) and that the coasting mode was activated at 13.20:36 (15.20:36
CET). Due to processing delays, it is not expected that the radar display will coincide with
the actual time of the last secondary surveillance data transmission; this may occur later.
The target data for flight MH17 was lost on the GKOVD radar screen at 13.20:58
(15.20:58 CET). At that moment the secondary radar label changed to xxxx. The
22 seconds between the label changes and the change to coasting mode on the UkSATSE
radar can be explained by the different software settings in the two radar systems



On the GKOVD video (see Appendix I), a second radar target, close to the MH17 labelled
target, was visible for 21 seconds between 13.20:47 - 13.21:08 and for 40 seconds
between 13.21:18 - 13.25:57 (15.20:47 - 15.21:08 and 15.21:18 - 15.25:57 CET). The second
target was considered to be aeroplane debris falling down and having suffcient reflection
to be detected as a primary target. This is consistent with the wind direction and fnal
position of the wreckage.
From the information provided by UkSATSE and GKOVD, there were no radar targets
other than the three commercial aeroplanes identifed in paragraph, either
commercial or military, displayed on the air traffc control screens within a range of 30 to
60 km to the south of flight MH17 and more than 90 km to the north and east and about
200 km to the west. There are no other unidentifed primary or secondary targets visible
within 30 km of flight MH17 in these data.
There are a number of factors that affect the ability of a civil primary radar system to
detect and display a small, fast-moving missile on a radar screen. The two most signifcant
are detection sensitivity and system fltering. Detection sensitivity refers to the power of
the radar system dictates how small an object can be detected and at what range it can
be detected. System fltering is intended to remove phenomena from a radar screen that
are detected but are not required to be displayed, e.g. rain. The high speed of the missile
may result in the radar system fltering the detected signal out of the images displayed
on the screen as it would, correctly, not appear to be the signal of an aeroplane.
It is concluded that it is very unlikely that the air traffc control primary radar systems in
the area could detect and display the missile on the air traffc controllers screen.

The raw UkSATSE surveillance radar data and the GKOVD radar screen video
replay showed that flight MH17 was on a straight and level flight at FL330 until
13.20:03 (15.20:03 CET).
Coasting tracks were observed on both sets of radar data. Coasting tracks were
shown on the GKOVD radar screen video replay of primary and secondary radar
from 13.20:03 (15.20:03 CET) and onward.
The GKOVD radar screen video replay from 13.20:47 - 13.21:08 and 13.21:18 -
13.25:57 (15.20:47 - 15.21:08 and 15.21:18 - 15.25:57 CET) showed targets which
are considered to be aeroplane debris falling down.
The radar information provided showed that the only aircraft in the direct vicinity
of flight MH17 were three commercial aeroplanes. There was no evidence of
other traffc in the vicinity of flight MH17.

3.4.3 Determining the events around 13.20 (15.20 CET)
This paragraph examines other, verifable, recorded data so as to analyse the hypothesis
that electrical power was lost at the moment that the recorders stopped recording.



In Section 2.11 it was established that the Cockpit Voice Recorder and Flight Data
Recorder both stopped recording at 13.20:03 (15.20:03 CET). In paragraphs and
3.4.2, it was shown that the transmission of radar surveillance data from flight MH17
ended at 13.20:03 (15.20:03 CET).
Following a fnal SATCOM transmission at 13.08:51 (15.08:51 CET), the ground systems
inactivity timer ran out approximately 15 minutes later, as it is programmed to do. An
attempt by the SATCOM system at 13.21:26 (15.21:26 CET) to establish connection with
the aeroplane from the ground was not successful.
A signal from the fxed Emergency Locator Transmitter was frst received at 13.20:35
(15.20:35 CET) by Geostationary satellites of the emergency COSPAS-SARSAT network.
According to the ELTs specifcations (see paragraph 2.11.5), an automatic, acceleration
or deceleration triggered, activation of the fxed Emergency Locator Transmitter has a 30
seconds delay. A manual activation, by a guarded switch located in the overhead panel
in the cockpit, of the fxed ELT has a delay of 50 seconds whereafter the ELT is activated
and detectable by Geostationary satellites. A second delay for both a manual or
automatic activation of approximately 1 or 2 seconds is expected due to signal latency
while going through the emergency satellite network.
Five ground stations received an Emergency Locator Transmitter signal which had been
relayed by two satellites between 13.20:35 and 13.20:36 (15.20:35 and 15.20:36 CET).
Considering the time of the receipt of the signal and the 50 second time delay on manual
activation, it was concluded that manual activation would have had to have occurred
around 13.19:45 (15.19:45 CET). This would have been recorded on the Flight Data
Recorder and, in all probability, on the Cockpit Voice Recorder. As this is not the case,
manual activation of the ELT is discounted.
The receipt of the signal, considering an automatic activation of the fxed ELT, with a time
delay of 30 seconds plus 1 or 2 seconds, would suggest an activation time between
about 13.20:05 - 13.20:06 (15.20:05 - 15.20:06 CET). The automatic activation was caused
by the Emergency Locator Transmitters G-switch detecting a longitudinal deceleration
of between at least 2.0 g and 2.6 g. This is consistent with the aeroplane breaking up
after the recorders stopped at 13.20:03 (15.20:03 CET).
A second ELT, a portable Emergency Locator Transmitter, was onboard that can only be
activated manually. No signal from the portable ELT was detected by the COSPASSARSAT emergency network.
The loss of the two recorders and the radar data at 13.20:03 (15.20:03 CET) indicated
that the electrical power was lost at this moment. The automatic activation of the fxed
ELT between 13.20:05 - 13.20:06 (15.20:05 - 15.20:06 CET), caused by a deceleration,
supported this. Finally, no other recorded data (e.g. SATCOM transmissions) contradicted
the hypothesis.
All times mentioned (in UTC only) that support this conclusion are set out in chronological
order in Figure 44.


Figure 44: Diagram showing a number of key moments in the recorded data. (Source: Dutch Safety Board)


Last UkSATSE radar acquisition
CVR recording ends /FDR recording ends/UkSATSE last message reception
(raw data)/UkSATSE last target detection (raw data)
UkSATSE mode S data no longer displayed
Fixed ELT activation detected
UkSATSE display enters coasting mode
GKOVD first appeared of primary targets around MH17 symbol
GKOVD MH17 label change to xxxx target lost
SATCOM no aeroplane response
GKOVD primary target no longer displayed

The Cockpit Voice Recorder and Flight Data Recorder stopped recording at
13.20:03 (15.20:03 CET) due to electrical power interruption.
The fxed Emergency Locator Transmitter was automatically activated by a
longitudinal deceleration of between at least 2.0 g and 2.6 g. Its signal was frst
detected between 13.20:35 and 13.20:36 (15.20:35 - 15.20:36 CET). System logic
means that the ELT was activated between about 13.20:05 and 13.20:06
(15.20:05 - 15.20:06 CET).

3.5 Possible sources of damage

In paragraphs 3.4.1 and 3.4.3 it was shown that shortly before the Cockpit Voice Recorder
stopped recording at 13.20:03 (15.20:03 CET), a high-frequency sound wave was
detected, originating outside the aeroplane from a position above the left hand side of
the cockpit propagating from front to aft. Shortly after the Cockpit Voice Recorder and
Flight Data Recorder stopped recording the Ukrainian and Russian Federation radar data,
SATCOM data and ELT activation data all show that the aeroplane suffered structural



failure and lost electrical power, experienced a deceleration (described in paragraph
3.4.3), and started to break up. The complete in-flight break-up sequence is analysed in
Section 3.10.
In this section the possible scenarios that could have led to the in-flight break-up of the
aeroplanes structure are described and analysed. Some of the scenarios were related to
internal aspects such as airworthiness, whilst others were related to external sources.
Those scenarios that were found not to be able to cause the damage noted (see Section
2.12) were, following analysis, excluded.
3.5.1 Lightning strike, meteor and space debris re-entry
Although there were thunderstorms in the area at the time of crash (see Section 2.7),
there was no evidence in the wreckage recovered or on the recorded data that a lightning
strike occurred that could have caused or exacerbated the high-energy object damage.
Based on the evidence provided by the Royal Netherlands Association for Meteorology
and Astronomy regarding the lack of ultranoise in Ukraine on the date of the crash as
described in paragraph, and the damage patterns on the aeroplane, it was
concluded that a meteor strike did not occur.
In addition, the possibility that space debris caused the crash was considered (see
paragraph The Aerospace Corporation database for 2014 showed no debris
re-entering the atmosphere between 10 and 19 July 2014.

The in-flight break-up was not caused by an external event such as a lightning strike,
the impact of a meteor or the re-entry of space debris.

3.5.2 Possible internal causes
The sound wave lasting 2.3 milliseconds that was recorded in the last 20 milliseconds on
the Cockpit Voice Recorder did not contain the same signature wave form as either an
internal explosion (bomb or fuel tank) or structural failure and explosive decompression.
Examples include the accident to flight PA103 at Lockerbie (Scotland) in 1988 and flight
TWA 800 off Long Island (United States of America) in 1996. In these two cases, the
sound signature was about 200 milliseconds long with the internal explosion building
very quickly to high value with a very short wavelength. The sound wave then dissipated
over time. In the case of structural failure and explosive decompression, the time is
similar but the peak noise was lower and the rate of dissipation was slower.



The form of the 2.3 millisecond sound wave did not match the signature waveforms
associated with structural failure and explosive decompression in a number of
previous aeroplane accidents.

Fuel tank explosion
A fuel tank explosion was not able to produce the sort of high-energy object perforation
from outside the fuselage.
Had a fuel explosion taken place, evidence of ruptured fuel tanks, with deformation of
the tanks pushing from the inside outwards should be found. The fuel tanks were not
recovered as they were destroyed in the fre at wreckage site number 6. However, the
fact that a large fre took hold on the ground is an indication that the fuel tanks were
reasonably intact and had a large quantity of fuel to feed the fre that took hold.

The in-flight break-up was not caused by a fuel tank explosion.

Uncontained engine failure
Another source of damage to the aeroplane was considered; an uncontained engine
failure. In such an event, high-speed rotating parts of the engine are freed from within
the engine intake ring. Such parts have suffcient energy to penetrate the fuselage. In
this case, the shape of the perforation holes did not resemble the shape that would be
caused by engine parts. In addition, an uncontained engine failure would not damage
the cockpit. The fuselage damage would be restricted to areas adjacent to the engine.
The analysis of the Flight Data Recorder data found neither evidence of a condition that
could lead to an uncontained failure or any other malfunction to the engines up to
13.20:03 (15.20:03 CET). On the basis of the above, an uncontained engine failure was
excluded as a possible cause of the damage to the aeroplane.

The in-flight break-up was not caused by an uncontained engine failure.

Detonation of an explosive device in the cabin/baggage hold
Whilst the break-up sequence of the fuselage described in Section 3.11 of this report had
some similarities with the failure and break-up sequences noted in accidents such as
those at Lockerbie in 1988, this crash differed with the Lockerbie accident and other
similar accidents in that the perforation was from the outside. An explosive device inside



the pressure hull of the aeroplane would not be able to produce the damage patterns
found in the wreckage; therefore an explosive device detonating inside the aeroplane
was excluded as a possible cause of the crash.

The in-flight break-up was not caused by the detonation of an explosive device
inside the aeroplane.

Fire due to dangerous goods or other baggage
With the exception of a single Lithium-ion battery, the review of the cargo manifest
described in paragraph 2.6.2 showed no evidence that any materials were being carried
that could have started a fre. There was no fre warning recorded on the Flight Data
Recorder and the crew made no mention of any such event, as recorded on the Cockpit
Voice Recorder.
As with the other scenarios, a fre inside the aeroplane would not be able to produce the
damage patterns found on the wreckage. Therefore, an on-board fre was excluded as a
possible cause of the crash.

There was no cargo classifed as dangerous goods on board the aeroplane, nor
was any evidence found of a fre caused by dangerous goods inside the
The in-flight break-up was not caused by an on-board fre.

3.5.3 Damage from external causes
As none of the potential causes of damage analysed were able to produce the damage
observed to the aeroplane and, in particular, the cockpit area, external causes were
further analysed.
In Section 2.12, hundreds of holes and ricochet marks that were observed on the forward
fuselage and in the cockpit are described. The interior of the cockpit, including the left
hand sides of the cockpit seats, showed evidence of large scale disintegration, extensive
crushing and had dozens of perforation holes. Section 2.12 also described the holes and
ricochet marks found on the left engine intake ring and the left wing tip.
The damage to the forward fuselage was concentrated in a band around the left hand
side of the fuselage starting adjacent to the cockpit windows 2 and 3. The concentration
is reduced rearwards of this area and ends ahead of the left hand forward passenger
door, door 1L. Some witness marks are also noted on the top of the cockpit just above
the windows

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