TAROM AT72 at Budapest on Mar 16th 2016, engine shut down in flight, smoke in cabin

Last Update: March 23, 2021 / 07:47:37 GMT/Zulu time

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Photo of Tarom YR-ATI, ATR ATR-72-200 — Tarom YR-ATI, ATR ATR-72-200 (Photo credit: ltbaspotter - Bulent Kavakkoru/SpotTR / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Mar 16, 2016

Classification
Incident

Airline
Tarom

Flight number
RO-236

Departure
Budapest, Hungary

Destination
Bucharest Otopeni, Romania

Aircraft Registration
YR-ATI

Aircraft Type
ATR ATR-72-200

ICAO Type Designator
AT72

A TAROM Avions de Transport Regional ATR-72-212A, registration YR-ATI performing flight RO-236 from Budapest (Hungary) to Bucharest Otopeni (Romania) with 19 passengers, was in the initial climb out of Budapest's runway 13L when the crew still on tower frequency declared Mayday, Mayday, Mayday initially not responding to queries by tower to say intentions. Subsequent radio transmissions from the aircraft were nearly unreadable and were not understood by tower, tower subsequently offered to contact approach for vectors or to fly a pattern for a return to runway 31R on tower frequency, the other pilot took over radio communication and chose to remain on tower frequency. The aircraft returned for a safe landing on runway 31R about 5 minutes after departure.

Passengers reported there was smoke developing in the cabin, the right hand engine was shut down in flight.

The airline reported that the crew received an abnormal indication from the right hand engine and returned to Budapest for a safe landing about 5 minutes after departure. The passengers were rebooked onto the next flight.

On Mar 25th 2016 The French BEA reported that the crew observed RPM fluctuations of the right hand engine during takeoff followed by an engine fire indication. The crew performed the engine fire drill, activated the fire suppression system and returned to Budapest. The occurrence was rated a serious incident and is being investigated by Hungary's Transportation Safety Board.

Some time in the past (around October 2018) the KBSZ released their final report concluding the probable causes of the serious incident was:

During the safety investigation, the IC concluded that the cause of the incident was that

– a blade of 1st stage PT of the engine №2 fractured as a consequence of a fatigue crack

Factors increasing the risk of a more serious outcome of the incident:

– The flight crew shut off the failed engine with delay.
– The flight lasted longer than the required minimum time.
– The aircraft taxied to the apron without being inspected after landing.

The KBSZ analysed:

Engine malfunction:

According to information from voice recordings and form the findings of the inspection of the engine, the engine failure took place as follows: A fatigue crack started out in the trailing edge of a PT1 blade, the spreading of which finally led fracture of the blade. The damage to other stator vanes and rotor blades of the power turbine was the consequence of the first blade fracture. The power turbine became unbalanced, and its intensive vibration caused fractures of the oil pipes and screws which fixed bearing housing # 6&7. The unsupported bearing housing could not keep the shafts in place, and the spilt oil caught fire. The low- and highpressure power turbine shafts may have contacted with each other and fractured.

The fire fuelled by spilt oil led to thermal damage to or deformation of the 1st stage PT stator, the low-pressure turbine, the bearing housing # 6&7, and the oil pipes. The HP turbine blades were damaged by overheating.

Flight crew activity:
(Altitude: AGL, Time: UTC)

Two seconds after the appearing of the audio and light signals warning of fire in the engine #2 (13:11:44), the flight crew set the power lever of the malfunctioned engine to idle, according to the requirements included in the emergency checklist. Feathering of the propeller and dropping of the fuel supply to the engine #2 to zero took place after a minute only (at 13:12:45). These facts show that subsequent steps of the emergency procedure (operation of the Condition Lever and the Fire Handle) were taken only at that time. From the moment of catching fire till the moment of propeller feathering the engine №2 autorotated at high temperatures (ITTmax=851ºC), which could have contributed to the serious internal damage to the engine. A non-feathered propeller creates a nonsymmetrical drag which affects the handling quality of the aircraft. Propeller was feathered one-minute after the engine failure.

In the case of engine fire, the emergency checklist requires landing with no delay: “LAND ASAP” (As Soon As Possible). When the fire warning appeared and the power lever of the malfunctioned (№2) engine was pulled the altitude of the aircraft was 604 - 676 ft (184 - 206 metres). Subsequently, the aircraft continued to climb for over 3 minutes (till 13:15:19), and reached a maximum altitude of 2565 ft (782 m). Consequently, when it turned back in the direction of the airport, it was too high to land “in a straight line”. The crew had to perform a descending, 360º left turn in order to take appropriate positon for a successful landing. All in all, the duration of the flight in the period between the appearance of the fire warning and actual landing was 8 minutes and 23 seconds, i.e. more than twice the time spent in the air by the type ATR (ATR42) aircraft involved in the fairly similar occurrence (our ref.: 2011-120-4P) mentioned in Section 1.18 above.

Activities of airport services:

After the landing, the ADC asked the flight crew of the aircraft (reg: YR-ATI, Flight: ROT236) whether they were able to taxi on their own. As the answer was positive, the ADC transferred the aircraft to the frequency of the GRC, who ordered the aircraft to taxi to the stand 220. Finally, upon order from the airport control service, the aircraft taxied to the stand 220 located at the apron of Terminal 2, in such manner that no one checked the state of the faulty engine or whether the engine fire – which had started during take-off and was detected even visually by the ATC – had been put off or was still burning.

Should the fire have still been burning onboard the aircraft, the fact of taxiing to the stand would largely have increased the risk of a more serious outcome of the occurrence, through the major causes as follows:

- The time spent on taxiing delays the start of fire extinguishing and evacuation.
- Other aircraft, vehicles and other objects staying at the apron may significantly hinder the movement of the people performing fire extinguishing or evacuation.
- The risk of spreading of the fire is much higher at the apron than on the runway or on the taxiways.

According to the procedure (1.17) recommended in Section 12.3.23 Part 1 of ICAO Doc 9137, an aircraft arriving with fire or smoke warning indication should only be allowed to taxi to the apron after it was checked whether the indicated fire hazard was real.