Aeroflot A320 near Budapest on Feb 3rd 2019, smoke in cockpit

Last Update: March 17, 2023 / 19:56:17 GMT/Zulu time

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Photo of Aeroflot VP-BMF, Airbus A320 — Aeroflot VP-BMF, Airbus A320 (Photo credit: Alec BHX/KKC / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Feb 3, 2019

Classification
Incident

Cause
Smoke in cockpit

Airline
Aeroflot

Flight number
SU-2097

Departure
Belgrade, Serbia

Destination
Moscow Sheremetyevo, Russia

Aircraft Registration
VP-BMF

Aircraft Type
Airbus A320

ICAO Type Designator
A320

An Aeroflot Airbus A320-200, registration VP-BMF performing flight SU-2097 from Belgrade (Serbia) to Moscow Sheremetyevo (Russia) with 99 passengers, was climbing through FL300 out of Belgrade when the crew detected smoke and a burning odour in the cocpit, cabin crew also reported smoke and a burning odour in the forward section of the cabin. The crew decided to divert to Budapest for a safe landing on runway 31R about 15 minutes after stopping the climb at about FL300.

The occurrence aircraft is still on the ground in Budapest about 27 hours after landing.

Hungary's KBSZ reported about 10 minutes after takeoff an odour was noticed in the forward cabin, then smoke was seen near the L1 main entrance door. The aircraft returned to Budapest for a safe landing. After landing the temperature at the cabin floor near the L1 door was measured at above 50 degrees C. The occurrence was rated a serious incident and is being investigated.

On Mar 17th 2023 Hungary's KBSZ released their final report concluding the probable cause of the serious incident was:

As a result of the investigation the IC concluded that the root cause of the incident was an electrical short circuit of the heating element due to corrosion of the outer edge of the heated floor panel with part number 4E4140-1.

The KBSZ analysed:

At the time of the incident, the problems with the failure of the aluminium skin heated floor panels were known to both the aircraft and the panel manufacturers (1.16, 1.18). The investigation of the floor panel had similar results to the examinations of malfunctions reported by the other operators prior to the incident. These results indicate that the short circuit of the heating element occurs among others due to mechanical damage and corrosion. The manufacturer of the panel has, as a definitive solution to these problems, developed a new titanium skin heated floor panel, which is stronger and therefore provide better robustness against mechanical impact, and the titanium skin is more resistant to the corrosion than the aluminium skin.

The information letters published by the aircraft manufacturer contain a solution for older floor panels in case the failure is associated with a short circuit and resulting smoke. It is highlighted that the heating circuit of the panels can be disconnected/isolated by pulling out the appropriate circuit breaker (CB) on the CB panel in the front galley of the aircraft. The procedure for this operation should be developed by the operators and incorporated in their own manuals. Based on the report received from the operator, the cabin crew operation manual and crew fire/smoke procedures were amended after the incident.

The information letters published by the aircraft manufacturer contain guidance on how to prolong the service life of these floor panels, avoiding the dropping of heavy and sharp objects and the use of excessively heavy trolleys. The IC also considers it important to mention that the service life of heated floor panels can be further extended by taking into account the weather conditions. In many cases, for example in the event of sudden rainstorm or heavy snowfall, the IC has found that the service staff often reacts too late to these circumstances and forgets to close the doors. In such cases, a lot of precipitation can reach the floor panels and places where it can greatly accelerate corrosion processes. According to the IC, this process can be greatly slowed down if more attention is paid to these conditions and how to avoid them.

As the aircraft manufacturer’s publications also provide guidance on how to deal with failures in the use of older aluminium skin floor panels in addition to the final solution, the IC does not propose to TSB issuing a safety recommendation.

In IC’s opinion similar failures could occur in the future, despite the fact that they are known to the manufacturer and operators. However, as regards the replacement of aluminium panels with titanium skin panels, the operator is the cost-bearer and its replacement is not mandatory, so the IC’s opinion is that the decision of the operator will be based on financial considerations. The probability of a more serious outcome than the failure in the present incident is low, but the cost of replacing the floor panel is high, and therefore the operator has presumably considered the possible risk to be negligible. In the opinion of the IC, that the manufacturer did not require the replacement of the floor panels with titanium skin ones because the possibility of a failure associated with fire is so small that, in their opinion, it does not require the issue of an airworthiness directive.