Thai A333 at Bangkok on Sep 8th 2013, runway excursion on landing

Last Update: October 25, 2023 / 10:23:51 GMT/Zulu time

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Incident Facts

Date of incident
Sep 8, 2013

Classification
Accident

Cause
Runway excursion on landing

Airline
Thai Airways

Flight number
TG-679

Departure
Guangzhou, China

Destination
Bangkok, Thailand

Aircraft Registration
HS-TEF

Aircraft Type
Airbus A330-300

ICAO Type Designator
A333

Airport
Suvarnabhumi Airport, Bangkok

Airport ICAO Code
VTBS

A Thai Airways Airbus A330-300, registration HS-TEF performing flight TG-679 from Guangzhou (China) to Bangkok (Thailand) with 287 passengers and 14 crew, landed on Bangkok's runway 19L at about 23:30L (16:30Z) but veered right off the runway and came to a stop with all gear on soft ground about 1700 meters down the runway, a large plume of dust rose above the aircraft initially creating fears of a crash followed by smoke from the right hand engine. The aircraft was evacuated via slides. 14 people received minor injuries in the evacuation with 3 of the injured still in hospital care 48 hours later, the aircraft received damage to both engines (PW4164), the nose gear and the right hand main gear, the nose gear is bent but did not collapse. The runway received substantial damage as result of the fracture of the right hand main gear bogie beam after the aircraft had travelled about 1000 meters down the runway following main gear touchdown.

Ground witnesses reported seeing sparks/fire at the right hand side of the aircaft during roll out. The right hand engine emitted smoke after the aircraft came to a stop, emergency services foamed the engine which stopped the smoke.

The airline reported (in their original Thai wording) that upon touchdown the nose gear caused a disruption which resulted in the aircraft to veer off the runway, their English translation reports a failure of the nose gear as cause of the aircraft veering off the runway. The captain took control of the aircraft and brought it to a stop. The airline confirmed 8 people received minor injuries as result of the evacuation and were taken to hospitals.

The airport authority reported that runway 01R/19L will not be available during entire Monday, Sep 9th (not yet reflected in NOTAMs). Emergency services attended to a right hand engine fire following the runway excursion. None of the gear struts has collapsed (contradicting media reports in Thailand reporting the nose gear had collapsed). The southern part of the runway was re-opened around noon local time, TORA 2000 meters.

A passenger reported that the aircraft touched down normally with its main gear, but when the nose gear touched down the aircraft veered violently to the right, the aircraft appeared to roll left first then right. When the aircraft came to a stop there was fire visible from the right hand side, an evacuation through the left hand doors was immediately initiated.

Thailand's Civil Aviation Authority reported on Tuesday (Sep 10th) that permission to move the aircraft off the runway has been granted, the works to release the runway fully back to service should be completed by midnight to Wednesday local time. The Authority added later in the day that the root cause of the runway excursion has been determined to be the fracture of the right hand main gear bogie beam. The cause of the fracture as well related events including the damage to the engines and engine fire are still being investigated.

On Sep 10th 2013 the airline said initial investigation results suggest that the aircraft had travelled about 1000 meters down the runway following a smooth landing when the right hand bogie beam broke and caused the runway excursion. The aircraft received substantial damage, especially on its right hand side and engine. Following the fracture of the bogie beam the right hand engine scraped along the runway surface causing sparks and some smoke, the actual cause of the following engine fire is still being investigated however.

The airport authority reported the airplane was moved off the runway area in the early morning of Wednesday Sep 11th 2013.

On Sep 11th 2013 at 15:30L (08:30Z) all works to return the runway to service were completed, the runway is back in service. Only taxiways B7 and B8 remain closed for another day.

The French BEA reported in their weekly bulletin on Sep 17th 2013 quoting Thai Authorities: "There was flame on both engines." Thailand's Accident Investigation Board is investigating the occurrence rated an accident.

In 2023 Thailand's Aircraft Accident Investigation Committee (TAAIC) released their final report concluding the probable cause of the accident were:

This accident caused by the fragmentation of the RH MLG bogie beam, made the aircraft veered off the runway. The aircraft fuselage and both engines were damaged, the right engine was on fire. However, the cause of damaged MLG bogie beam could not be found due to the cracks were damaged while the aircraft was scraping the runway surface.

Contributing Factors

- Errors occurred during the overhaul of the RH MLG bogie beam.

- Errors occurred during the inspection of the RH MLG bogie beam pivot pin bore.

- Errors occurred during the repetitive inspection of the RH MLG bogie beam internal surfaces, as per the EASA AD No. 2007-0314R1, issued on 31 January 2008, the EASA AD No. 2008-0093, issued on 20 May 2008, the EASA AD No. 2011-0141, issued on 25 July 2011 and the EASA AD No. 2012-0015, issued on 23 January 2012, due to misinterpretation.

- The DCA has the power to regulate the six-monthly maintenance report form, as prescribed in Section 41/80 (2) of the Air Navigation Act B.E.2497. However, the maintenance review checklist did not specify what items had been performed, only a clause mentioned that the maintenance had been completed. The air operator then had no guidance to create maintenance list of items that had completely and correctly been performed.

- The content in the EASA ADs firstly states that unless already accomplished or required as indicated, unless accomplished previously which might cause confusion among the operators.

- Airbus S.A.S has the data on which MLG bogie beam had the internal surfaces inspection done before the designated time frame prescribed in new ADs. However, the company did not notify those air operators.

The TAAIC analysed:

The weather was not a contributing factor to the accident.

The landing operation was normal.

The aircraft systems and both engines functioned normally.

Both engines were damaged by the ingestion of some foreign object debris into the aircraft engine while the aircraft veered off the runway.

The right main landing gear (RH MLG) bogie beam broke after the aircraft touched down on runway, which caused the aircraft collapsed to the right and veered off the right side of the runway until it stopped on the runway strip.

The laboratory investigation results of the broken MLG bogie beam consisting of the forward part, the central part and the aft part, from Messier-Bugatti-Dowty Laboratory, Gloucester, the United Kingdom, associated with the representatives from the Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA), the Republic of France and the Air Accident Investigation Branch (AAIB) , the United Kingdom showed that:

The initiation site of the bogie beam fracture could not be found. Therefore, the precise mode of crack initiation and propagation could not be determined.

Corrosion pits were found and believed that they occurred before the last overhaul.

The thickness of the paint layers were below specification and believed to have been applied thin at overhaul.

Areas within the bogie pivot bore were found without the presence of Ardrox AV100D coating believed to have been removed and subsequently not replaced at the RH MLG Bogie Pivot Pin inspection in March 2013.

The presence of corrosion pits that were undetected at last overhaul could potentially reduce the time from onset of corrosion in the pit to initiation of a stress corrosion crack. If onset of corrosion of the pit was to occur after overhaul, this could potentially lead to bogie fracture in a shorter time period than corrosion starting after overhaul on a non-pitted surface. It should be noted that for the only previous case of in-service bogie fracture, serial number 328, the pit depth at fracture was 0.67 millimetres compared to a maximum pit depth of 0.2 millimetres on the RH MLG bogie beam. In addition, no evidence of corrosion re-starting after last overhaul was observed in the pits formed by corrosion prior to last overhaul on the RH MLG bogie beam.

Thai Airways International Public Company Limited did not repeat the inspection of the internal surfaces of MLG bogie beam, as required in the Airworthiness Directive (AD) issued by the European Aviation Safety Agency (EASA) No. 2007-0314R1, issued on 31 January 2007, the EASA AD No. 2008-0093, issued on 20 May 2008, the EASA AD No. 2011-0141, issued on 25 July 2011 and the EASA AD No. 2012-0015, issued on 23 January 2012, because the company considered that the accomplishment of the EASA AD No. 2007-0314, issued on 13 May 2007, was compliance with requirement of four above-mentioned ADs.

Section 41/80 (2) of the Air Navigation Act B.E.2497 prescribed that the air operator to make a maintenance report for the aircraft, and submit it to the Director General every six months. However, the maintenance review checklist did not specify what items had been performed, only a clause mentioned that the maintenance had been completed. The Department of Civil Aviation therefore could not conduct the detailed inspection.

Recorded data from Airbus S.A.S. in October 2013 showed that there were 53 MGL bogie beams had the internal surfaces inspection done before the effective of new ADs. It was believed that the misinterpretation of ADs contents might be the cause.

Airbus S.A.S. obviously had the data on which MLG bogie beam that had accomplished the internal surfaces inspection before the designated time frame.

The content in the EASA ADs firstly states that unless already accomplished or required as indicated, unless accomplished previously which might cause confusion among the operators whether the required actions have been accomplished in accordance with such ADs.

Metars:
VTBS 081730Z VRB01KT 9999 FEW020 BKN120 BKN300 25/22 Q1012 NOSIG
VTBS 081700Z 00000KT 9999 FEW020 BKN120 BKN300 25/22 Q1012 NOSIG
VTBS 081630Z 00000KT 9999 FEW020 BKN120 BKN300 26/23 Q1012 NOSIG
VTBS 081600Z 00000KT 9999 FEW020 BKN120 BKN300 26/22 Q1012 NOSIG
VTBS 081530Z VRB01KT 9999 FEW020 BKN120 BKN300 26/22 Q1013 NOSIG
VTBS 081500Z VRB01KT 9999 -RA SCT020 SCT035 BKN120 26/22 Q1013 NOSIG
VTBS 081430Z 25005KT 200V290 9999 -RA SCT020 SCT035 BKN120 26/22 Q1012 NOSIG
VTBS 081400Z 24003KT 180V330 9999 FEW020 BKN120 BKN300 26/23 Q1012 NOSIG
VTBS 081330Z 22003KT 9999 FEW020CB BKN120 BKN300 26/23 Q1011 CB S NOSIG
VTBS 081300Z 15003KT 110V190 9999 FEW020CB BKN120 BKN300 27/23 Q1010 CB SW NOSIG

Related NOTAMs:
A3191/13 - TWY B7 AND TWY B8 CLSD DUE TO WIP. 11 SEP 13:40 2013 UNTIL 12 SEP 23:00 2013. CREATED: 11 SEP 13:41 2013

A3157/13 - DUE TO DISABLED AIRCRAFT ON RWY 01R/19L, THE REMAINING PORTION
OF A RWY 01R/19L, RWY 01R IS NOT ALLOWED TO TKOF AND LANDING,
RWY 19L IS ALLOWED TO TKOF ONLY AT THE PSN AS FOLLOWING
A. AIRCRAFT ENTERS RWY 19L TO TKOF PSN VIA TWY B8 AND THEN TURNS
RIGHT TO FACE SOUTH FOLLOWING YELLOW GUIDELINE AND TAXI TO TKOF
PSN DISPLAYED BY THE TRANSVERSE WHITE MARKING, TORA IS 2000M
B. AIRCRAFT ENTERS RWY 19L TO TKOF PSN VIA TWY B7 FOLLOWING YELLOW
GUIDELINE TO TKOF PSN DISPLAYED BY TRANSVERSE WHITE MARKING,
TORA IS 1700M
C. RWY EDGE LGT, RWY CENTERLINE LGT, RWY END LGT IN THIS PORTION
OF RWY 19L ARE SERVICEABLE
D. CLOSED TWY:B1, B2, B3, B4, B5 AND B6
E. AIRCRAFT USING THIS SHORTENED RWY SHOULD BE CODE C OR BELOW
F. AIRLINE SHOULD HAVE ADDITIONAL RESERVED FUEL DUE TO POSSIBLE
FLIGHT DELAYS. 09 SEP 05:30 2013 UNTIL 11 SEP 02:00 2013. CREATED: 09 SEP 05:32 2013

A3152/13 - RWY 01R/19L CLSD DUE TO DISABLE ACFT. 08 SEP 17:45 2013 UNTIL 09 SEP 01:00 2013. CREATED: 08 SEP 17:46 2013