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DRAFT REPORT

2007-510-4 SERIOUS INCIDENT

Budapest 12 December 2007.

AIRBUS A320-214 VP-BQW

The sole objective of the technical investigation is to reveal the causes and circumstances of aviation accidents, incidents or irregularities and to initiate the necessary technical measures and make recommendations in order to prevent similar cases in the future. It is not the purpose of this activity to apportion blame or liability.

Concerning this draft report, the organizations, services and crew members defined by the relevant decree can make reflections within 60 days from the date of delivery/receipt, which are to be evaluated when compiling the final report. Therefore this present draft report is not the final position of the investigator and cannot be published.

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This present investigation was carried out on the basis of

− Act XCVII of 1995 on aviation,

− Annex 13 of MTCW (Ministry of Transport, Communications and Water) Decree 20/1997. (X. 21.) on the declaration of the annexes of the Convention on International Civil Aviation signed in Chicago on 7th December 1944,

− Act CLXXXIV of 2005 on the technical investigation of aviation, railway and marine accidents and incidents (hereinafter referred to as Kbvt.),

− MET Decree 123/2005 (XII. 29.) on the regulations of the technical investigation of aviation accidents, incidents and irregularities,

− In absence of other related regulation of the Kbvt., the Transportation Safety Bureau of Hungary carried out the investigation in accordance with Act CXL of 2004 on the general rules of administrative authority procedure and service,

− The Kbvt. and the MET Decree 123/2005 (XII. 29.) jointly serve the compliance with the following EU acts:

a) Council Directive 94/56/EC of 21 November 1994 establishing the fundamental principles governing the investigation of civil aviation accidents and incidents, with the exception of its Annex;

b) Directive 2003/42/EC of the European Parliament and of the Council of 13 June 2003 on occurrence reporting in civil aviation, with the exception of its Annex I and Annex II.

− The competence of the Transportation Safety Bureau of Hungary is based on the Kbvt. until 31st December 2006 and on Government Decree 278/2006 (XII. 23.) from 1st January 2007 respectively.

Under the aforementioned regulations − The Transportation Safety Bureau of Hungary shall investigate aviation accidents

and serious aviation incidents.

− The Transportation Safety Bureau of Hungary may investigate aviation incidents and irregularities which - in its judgement - would have resulted in accidents in other circumstances.

− The technical investigation is independent of any administrative, infringement or criminal procedures.

− In addition to the aforementioned laws, the ICAO DOC 6920 Manual of Aircraft Accident Investigation is applicable.

− This present Draft Report shall not be binding, nor shall an appeal be lodged against it.

Persons participating in the technical investigation did not act as experts in other procedures concerning the same case and shall not do so in the future.

The IC shall safe keep the data having come to their knowledge in the course of the technical investigation. Furthermore the IC shall not be obliged to make the data – regarding which the owner of the data could have refused the disclosure of the data pursuant to the relevant act – available to other authorities.

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Abbreviations and definitions

CORE COMPARTMENT

The section of the engine that includes the combustor, the low pressure and the high pressure turbine and the adjoining parts

DTSB Dutch Transport Safety Board

HMU Hydromechanical Unit

IC Investigating Committee

ICAO International Civil Aviation Organization

JTM Joint Technical Meeting

Kbvt. Act CLXXXIV of 2005 on the technical investigation of aviation, railway and marine accidents and incidents

LHTB Lufthansa Technik Budapest

LPTCC Low Pressure Turbine Clearance Control

MEL Minimum Equipment List

MET Ministry of Economy and Transport

MTCW Ministry of Transport, Communications and Water (Közlekedési, Hírközlési és Vízügyi Minisztérium, KHVM)

NTA DAT National Transport Authority, Directorate of Air Transport

QAR Quick Access Recorder

QRH Quick Reference Handbook

Shop Visit Check conducted in an overhaul facility

TSB Transportation Safety Bureau (of Hungary)

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SYNOPSIS

Occurrence category serious incident manufacturer AIRBUS Industrie model A320-214 registration VP-BQW serial number 2947 owner GAL HOLDINGS LIMITED

Aircraft

operator AEROFLOT Russian Airlines date and time 12 December 2007.

occurrence location Budapest/Ferihegy fatal 0 injuries

serious 0 aircraft damage Reparable state of registry Bermuda Islands registering authority Department of Civil Aviation Bermuda authority supervising manufacturing DGAC France

Notifications

The occurrence was reported to the duty services of TSB by the Ferihegy Airport OPS at 13:38 minutes on 12th December 2007.

The on duty personnel of TSB reported the occurrence to TSB’s head of department on duty at 13 hours 39 minutes on 12th December 2007, then to the on duty personnel of NTA DAT at 13 hours 42 minutes.

Investigating committee

The Director-General of TSB appointed the following Investigating Committee (hereinafter referred to as IC) on 12 December 2007:

• László STORCZER, Investigator-in-Charge (IIC) • Zsófia OLÁH, investigator • Ferenc PATAKI, field investigator/technician

Summary of the investigation

The aircraft landed normally at 13:50 (LT) and stopped on the runway. The site survey team arrived to the scene at 13:55 (LT). A strong smell of kerosene could be felt around the aircraft, and the team discovered several mechanical damages, namely the separation of the upper layer of the left main landing gear tyre, a damaged compressor of the left engine, and the damaged flaps of the left wing. The passengers were disembarked at 14:10 (LT) and the aircraft was towed by LHTB personnel to their hangar. The detailed survey of damages and their repair was done at LHTB, while the expert analyses were conducted in Moscow and in Tilburg.

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1. FACTUAL INFORMATION

1.1 History of the flight Flight AFL583, operated by Aeroflot, was flying a scheduled route according to IFR rules, between FCO-SVO, aircraft registration VP-BQW, on 12 December 2007. The previous SVO-FCO flight was completed without problems. The captain completed the walk-around and did not find any irregularities at the tyres. The pilots started the engines at 10:50 (UTC) and after a six-minute taxiing initiated the take-off from runway 34L of Rome-Fiumicino airport at 10:56 (UTC). At the moment of rotation, at a speed of 158 kts the upper layer of the left main landing gear’s inner tyre got separated from the carcass of the tyre, and the centrifugal force sent it flying in several pieces. The left engine that was at take-off power sucked in some pieces that caused substantial damage to the front row of low pressure compressor blades. Deformation of the blades led to disbalance of the low pressure compressor. Vibration of the left engine increased from 0.8 units to 9.2 on a 10-unit scale, and went back to 3 units only after the engine thrust had been reduced. According to the Commander’s Report, the crew noticed the vibration and the smell of burnt rubber at take-off but they thought they had a separation on the nose gear tyre. They checked the engine parametres and the captain decided they would continue the flight according to the flight plan. They were flying at FL360 when in the 75th minute into the flight they noticed a fuel imbalance, the left wing tank had about 500 kg less fuel than the right. The captain went back to the main cabin to check the engines, and he saw fuel vapor in the the left engine exhaust. The captain, in accordance with the QRH, Abnormal Procedures chapter, at 12:21 (UTC) decided to shut down the left engine and at 12:26 (UTC) while flying near Sajóhídvég requested clearance for landing at Budapest Ferihegy. The crew did not report the ATC about the engine shutdown, they stated suspected fuel leak as the reason for the landing request. They did not declare emergency, they just requested priority landing and fire-service for the landing, and also told the ATM that due to a possible nose gear problem they won’t be able to leave the runway. The aircraft successfully landed at 12:47 (UTC) on runway 31R. During the landing, more pieces got separated from the damaged tyre’s upper layer which broke the brake hydraulics line in the landing gear bay, and also damaged the 1/B section of the left wing’s flaps. The aircraft was able to stop on the runway. After a short technical check the passengers were disembarked and the aircraft was towed to the LHTB hangar.

1.2 Injuries to persons There was no injury.

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1.3 Damage to aircraft During take-off from Rome-Fiumicino the upper layer of the left main landing gear #2 tyre (on the inside wheel) got separated from the carcass of the tyre, and its pieces flew away. The #1 engine sucked some pieces that caused substantial damage to the fan blades of the low pressure compressor. Due to the imbalance of the rotor, the vibration increased and the fuel line running to the LPTCC fuel manifold on the right hand side of the engine broke. During landing at Budapest, more pieces got separated from the damaged tyre’s upper layer which broke the brake hydraulics line in the landing gear bay, and also damaged the 1/B section of

the left wing’s flaps.

1.4 Other damage

1.5 Personnel information

1.5.1 Pilot-in-Command

Age and gender 55-yr-old male Pilot licence valid until valid

Medical certificate valid until valid

Licence in accordance with regulations

Licence data

Ratings in accordance with regulations Total 14902 hrs in the last 30 days 81 hrs in the last 7 days n/a

Total flight hours / number of take-offs

in the last 24 hrs n/a On the given type 3000 hrs

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1.5.2 First Officer

Age and gender 24-yr-old male Pilot licence valid until valid

Medical certificate valid until valid

Licence in accordance with regulations

Licence data

Ratings in accordance with regulations Total 1300 hrs in the last 30 days 88 hrs in the last 7 days n/a

Total flight hours / number of take-offs

in the last 24 hrs n/a On the given type 120 hrs

1.6 Aircraft information

1.6.1 Airworthiness certificate The registering authority completed the airworthiness verification check of the aircraft on 28 November 2007, and extended the validation of the airworthiness certificate until 27 November 2008.

1.6.2 General information flight hours number of landings

Since manufacturing 1364 2713

1.6.3 Engine data flight hours

Since manufacturing 1364 Since last maintenance n/a

1.6.4 Data on the defective equipment/part

Date of manufacturing n/a Date of installation on aircraft 8 September 2007

1.6.5 Aircraft loading data Not applicable.

Type of fuel used: Jet A1

Aircraft data had no effect on the course of events therefore their analysis was not required.

1.7 Meteorological information The meteorological parameters had no effect on the course of events therefore their analysis was not required.

1.8 Aids to navigation The characteristics of the navigation instruments had no effect on the course of events therefore their analysis was not required.

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1.9 Communications The characteristics of the communications instruments had no effect on the course of events therefore their analysis was not required.

1.10 Aerodrome information The characteristics of the aerodrome had no effect on the course of events therefore their analysis was not required.

1.11 Data recorders The aircraft was equipped with an on-board flight data recorder (FDR) and a cockpit voice recorder (CVR) in accordance with the aircraft’s airworthiness certificate. The aircraft also had a QAR installed; the evaluation of QAR data were useful for the investigators.

1.12 Wreckage and impact information There was no wreckage.

1.13 Medical and pathological information The pilots of the aircraft had valid medical certificates prior to the commencement of the flight. The IC does not have information on the pilots’ psycho-physical condition during the flight.

There was no pathological examination.

1.14 Fire There was no fire.

1.15 Survival aspects There was no life-threatening situation. There was no injury.

1.16 Tests and research There was no need to conduct tests and research for reaching the conclusion.

1.17 Organizational and management information The characteristics of the organizational and management environment had no effect on the course of events therefore their analysis was not required.

1.18 Additional information The IC does not intend to release more information other than the factual information above.

1.19 Useful or effective investigation techniques The investigation did not require techniques differing from the traditional approach.

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2. ANALYSIS The IC started the investigation with the examination of damaged parts in order to determine the chain of events. The captain told the IC during the interview that he personally checked the tyres during walk-around at Rome-Fiumicino and did not find anything abnormal. Two days after the incident, specialists of Aeroflot arrived from Moscow to join their Lufthansa Technik colleagues in the troubleshooting and restoring the airworthiness of the aircraft. The aircraft was equipped with a QAR, and the evaluation of downloaded data helped to reconstruct the chain of events that led to the incident.

The pilots started the engines at 10:50 (UTC) and after a six-minute taxiing initiated the take-off from runway 34L of Rome-Fiumicino airport at 10:56 (UTC). At the moment of rotation, at a speed of 158 kts the upper layer of the left main landing gear’s inner tyre got separated from the carcass of the tyre, and the centrifugal force sent it flying around in several pieces. The left engine that was in take-off power sucked in some pieces that caused substantial damage to the front row of low pressure compressor blades. Seven compressor blades had to be replaced. Due to the deformation of the low pressure compressor blades, the engine vibration at the fan stage increased. The vibration intensity started to increase at 10:56 (UTC) from 0.8 units to 9.2 units in one minute. The vibration indicator is calibrated up to 10 units, where one unit is equivalent to a vibration of 0.3 inch/sec. Because of the intense vibration, at 11:07 (UTC) the fuel line that feeds the LPTCC valve on the right hand side of the engine broke near the fuel manifold, just above the velding. The broken line spilled fuel onto the turbine housing

until 12:26 (UTC) when the engine was shut down. The temperature in this area is around 200 oC while in flight. For seventy-nine minutes there was a dangerous situation because the fuel could have ignited at any time.

SNECMA, the manufacturer of the CFM engines, in its reply to the IC’s inquiry, noted that the incident with Aeroflot VP-BQW aircraft was the tenth occasion in four years when the fuel line – part number P/N 336-401-402-0 - broke. All events involved a CFM56-5B engine and were caused by extreme vibration of the fan stage of the compressor. SNECMA has already initiated a new design for the fuel pipe. Fortunately,

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none of the pipe fractures caused fire. The core compartment of the engine is a zone of high risk of fire, and is equipped with a fire suppression system. Parts of the system are two fire detectors that are able to identify the source of the fire and provide indication in the cockpit. The fire suppression system can be activated by the pilots. During the 2008 CFM56 Joint Technical Meeting the manufacturer briefed the FAA and EASA representatives on SNECMA’s ongoing work on the new fuel pipe design and the enhanced fire suppression system that would provide better flight safety. Both authorities accepted the Airbus’ plan. A year earlier, both organisations expressed their concerns with regard to the similar occurrences in the past.

The size of the fuel pipe – if broken in the full cross-section, as it was in this case - allows to spill 450 litres of kerosene per hour, the weight of which is 500 kg. This 500 kg difference between the sides was visible on the cockpit fuel indicator.

This graphic depicts the fuel system of the CFM 56-5B engine. Within the HMU there are two distinctive systems: a low pressure system that supplies the auxiliary equipment, and a high pressure system that feeds the fuel nozzles. The location of the pipe fracture is marked with a red „X” sign. It is evident that the fuel flow through the broken line is not indicated by the fuel consumption instrument because, in normal cases, there is no fuel consumption. It means the pilots had no knowledge of the fuel leak. Since each engine receives fuel from its correspondent wing tank, the only indication of the fuel leak was the 500-kg difference of fuel reserve between the wing tanks.

The operator sent both tyres of the left main landing gear to the manufacturer’s (Goodyear) laboratory at Tilburg, The Netherlands, for analysis. Upon TSB’s request, a representative from the Dutch Transport Safety Board supervised the examination. The DTSB sent the examination report to TSB. The tyre (Serial No. 71741759) was installed on the landing gear’s #2 position of the VP-BQW aircraft on 8 September 2007. The aircraft has completed 361 landings with the tyre from its installation to the incident.

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The tyre pressure was within the operational limits at the time of the check, however, the manufacturer determined by the skid depth markings (the wear was 73%) that the tyre had been operated on low pressure which caused the separation of layers. Due to the low pressure, the tyre got hot above normal temperature during roll – especially in turns – which set off a separation process. The cohesion between the upper layer and the layer beneath it degraded in time, and during the take-off at Rome-Fiumicino the centrifugal forces tore off the upper layer. The other tyre also showed signs of degradation and wear, albeit in a much lesser degree. This can be a consequence of the fact that due to the underinflated tyre, the other one got overloaded.

The worn tyre A regular tyre

The break assembly was sent to shop visit upon request of TSB because the LHTB specialists found the two break actuators fully extended and stuck. LHTB did not have a spare of the assembly in stock, therefore the aircraft was flown to Moscow without passengers, with its left main gear brake assembly deactivated, in accordance with MEL regulations. The #2 assembly was then removed from the aircraft and sent for check to an overhaul shop. According to the shop visit report, the break assembly (Serial No. 7632) passed the check without findings and was operational at the time of the incident.

The IC analysed the crew’s actions to check if they followed the regulations and procedures.

The captain checked the landing gears during walk-around. There were no visual signs of the layer separation.

During take-off, the pilots felt smell of burnt rubber and noticed a strong vibration. They believed they had a separation on the nose gear tyre and that caused the vibration. All engine parametres were normal except for the vibration value. The vibration decreased to 5 units after the pilots reduced engine thrust after take-off, and it further decreased to 3 units on cruising altitude. The QRH, ABNORMAL PROCEDURES chapter, paragraph 2.24 requires the check of engine parametres if the vibration is above 5 units. Presence of a vibration itself does not require the shutdown of the engine, if other parametres – especially the gas temperature in the turbine – are within the operational range. Should the vibration increase over 5 units, the engine thrust has to be reduced, but the flight can be continued.

When the crew noticed the 500-kg fuel imbalance developed because of the fuel leak, they started to search for the cause of the imbalance. The captain went back to the main cabin and visually checked both engines. He saw the fuel vapors, and after consulting the QRH he decided to shut down the #1 engine and to abrupt the flight, and requested an immediate landing at Budapest. The QRH, ABNORMAL PROCEDURES chapter, paragraph 2.08 on „FUEL LEAK” prescribes the following procedure:

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If visibility permits, leak source may be identified by a visual check from the cabin.

WHEN A LEAK IS CONFIRMED

LAND ASAP

LEAK FROM ENGINE/PYLON CONFIRMED: Engine fuI leak can be confirmed by excessive fuei flow indication, or a visual check

— THR LEVER (of affected engine) IDLE

— ENG MASTER (of affected engine) OFF

— FUEL X FEED USE AS RQRD It the leak stops, the crossfeed valve can now be opened to re-balance fuel quantity, or to enable use ot fuel from both wings. Do not restart the engine.

The pilots acted in accordance with the above procedures.

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3. CONCLUSIONS

3.1 Direct cause(s) of the occurrence • The first event in the chain that led to the incident was the separation of the

upper layer of the left main landing gear’s inner wheel tyre from the carcass. The separation was set off by the operation of the tyre with a low pressure outside the normal operational range.

• The #1 engine sucked some pieces of the separated rubber layer.

• The ingested pieces caused substantial damage to the fan blades of the low pressure compressor.

• Due to the imbalance of the rotor, the vibration of the compressor’s fan section increased.

• Due to the increased vibration the fuel line running to the LPTCC fuel manifold on the right hand side of the engine broke.

• The broken line spilled fuel onto the turbine housing for about seventy-nine minutes.

• The fuel leak caused a fuel imbalance between the two wing fuel tanks.

• The pilots followed the QRH rules and made an emergency landing on RWY 31R of Budapest-Ferihegy.

3.2 Indirect cause(s) of the occurrence Not applicable.

3.3 Risk factors that are not related to the occurrence Not applicable.

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4. SAFETY RECOMMENDATIONS BA2007-510-4_1: The IC suggests the Aeroflot Russian Airlines:

• to make sure that its aircraft are operated with fully inflated tyres;

• to revise – and, if necessary, amend – the maintenance manual regarding tyre pressure check and setting during the Daily Check, taking into consideration the Airbus AMM and the Goodyear CMM documentation;

• to submit the revised AMM to the registering authority for approval.

Budapest, „ „ November 2008.

László STORCZER

IIC Ferenc PATAKI

IC member

NOTE:

This present document is the translation of the Hungarian version of the Draft Report.

Although efforts have been made to translate it as accurately as possible, discrepancies may occur.

In this case, the Hungarian is the authentic, official version.