Covering form of preliminary or final report
| Date of event : | 2020-01-16 |
| Incident number : | CZ-20-0024 |
| Report : | Final report |
| Place of event : | Brno Turany Airport |
| Registration mark : | Serious incident |
| Weight category MTOM: : | <2250 kg |
| Type of operation : | Recreational and sport aviation |
| Plane / SFM : | Airplanes |
| Type of plane / SFM : | Zlín Z-42 M |
| Health effects of event : | Without injury |
| PDF document : | 
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Description:
SUMMARY
Overview
On 16 January 2020, at 14:55, RCC and subsequently an aircraft operator reported a serious incident at LKTB to the AAII. Shortly after take-off from RWY 27, the pilot of Z-42 M aircraft issued a distress message by sending “MAY DAY”, requesting an immediate landing at the aerodrome due to smoke on board and possible fire.
The aircraft safely landed on RWY 09 and stopped on TWY B. When the FRS arrived, they checked the aircraft. There were no signs of fire on the aircraft, so it was towed to the operator’s hangar for further inspection.
Neither any serious injury nor any damage were sustained during the serious incident.
Factual Information
On 16 January 2020, the pilot carried out pre-flight preparation for the planned flight activity, which was supposed to consist of flights on the LKTB circuit. After that, at 13:35, he started pre-flight inspection of the aircraft. Subsequently, he had the technician tow the aircraft to the NORTH parking area. Having performed all the “after entering the cockpit” tasks, he started up the engine and was warming it up at 1,500 rpm. When the engine was warming up, the pilot contacted TWR and requested clearance for local operation – flight on a circuit. He received clearance for the operation as well as for taxiing to the holding position on TWY C for the expected take-off from RWY 27.
At the holding position on TWY C, he conducted engine test run, instrument scan, and pre-take-off operations. At 14:48, the pilot received clearance to enter the runway and take off from RWY 27.
Having taken off, approximately 50 m above the ground, he smelt a burning odour and shortly after that saw smoke in the cabin. At once, he declared “MAY DAY” – fire on board and requested immediate landing. He received clearance for final leg and landing on RWY 09. The pilot performed a right turn by 180 degrees for the final approach on RWY 09. The aircraft landed in order at 14:51. After landing, the aircraft vacated RWY 09 to TWY B and stopped there. The pilot turned off the engine, closed the fuel feed, shut off electric power supply, and deplaned. FRS emergency vehicles arrived at the aircraft location on TWY B. The Fire Rescue Service team inspected the aircraft which seemed undamaged on the outside as there was no visible fire or signs of fire. However, the aircraft cabin smelt of burning and smoke. The aircraft was subsequently towed with the FRS assistance to the NORTH parking area for further inspection and identification of smoke cause. After the engine cover was opened, on the left side, a detached plastic deflector from the left cooling air intake was found on the exhaust pipe behind the silencer. Because of the heat, the deflector became glued onto the exhaust pipe and started melting.
Neither any injury nor any damage were sustained during the incident.
Analysis
The weather was suitable for the flight performance and no dangerous meteorological phenomena occurred at the given location. The pilot held the necessary qualification and was medically fit for performing the given flight. He had experience with flying on this type.
Until the incident, the aircraft was airworthy and in good technical condition. The weight and the centre of gravity were within the permitted limits and had no impact on the occurrence of the event.
The weather was suitable for the planned flight activity and had no effect on the cause of the event.
While the aircraft was taxiing, the plastic deflector had been probably already detached from the left cooling air intake. Due to deflector shape strain caused by heat, the cause of deflector detachment could not be identified. The detached plastic deflector fell down to the lower left part of the engine compartment where it melted onto the exhaust silencer outlet. During take-off, when the exhaust system temperature is higher in the take-off mode, it started melting. In the course of this process, the plastic started releasing toxic fumes (hydrogen chloride and carbon monoxide) and then smoke.
Should the deflector plastic be exposed to long-term thermal effect, despite its self-extinguishing properties, the melting plastic was highly likely to catch fire which could have then spread in the engine compartment. The pilot’s responses and decisions were correct. Any delay would very likely lead to outbreak of fire.
Causes
The serious incident was caused by a detached plastic deflector from the cooling air intake which fell onto the exhaust pipe where the plastic deflector started melting due to the high temperature and triggered a thermal chemical reaction releasing toxic fumes and smoke.