ASN Wikibase Occurrence # 224901
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| Date: | Saturday 14 July 2018 |
| Time: | 15:40 UTC |
| Type: |  Aérospatiale SA341G Gazelle |
| Owner/operator: | Private |
| Registration: | YU-HMC |
| MSN: | 1136 |
| Year of manufacture: | 1974 |
| Engine model: | Turbomeca (Safran) Astazou 3A |
| Fatalities: | Fatalities: 0 / Occupants: |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Enfield, Greater London -
 United Kingdom
|
| Phase: | Take off |
| Nature: | Ferry/positioning |
| Departure airport: | |
| Investigating agency: | AAIB |
| Confidence Rating: |  Information verified through data from accident investigation authorities |
The helicopter was parked at the bottom of the pilot’s garden while some building works were being carried out. The pilot intended to take off and position the helicopter nearer his house so he could clean and polish it, and then depart to Elstree for fuel. The takeoff weight with the pilot and 325 kg of fuel onboard was 1,524 kg (MTOW 1,800 kg). The wind was calm and the air temperature was 30°C.
After carrying out his usual daily inspection and pre-flight checks the pilot lifted off into a 5 to 10 ft hover. All checks were normal. He then moved forward and initiated a right turn. During the right turn he perceived that the engine had lost power. He tried to return to the takeoff site but came down about 20 metres short. The ground there was uneven with some large wooden pallets and other building materials. The pilot thought the helicopter probably struck one of the pallets and then rolled onto its side, with the rotor blades striking the ground.
The pilot instinctively climbed out and moved rapidly away from the helicopter. He had omitted to operate the emergency fuel shutoff lever and he could hear the engine running, at low power, as he left the helicopter. He could see steam or smoke so he fetched a fire extinguisher. When he returned the helicopter was on fire with large amounts of smoke.
The fire service had been notified of the fire by a passer-by and arrived on scene 8 minutes after the call, at 1551 hrs. The fire service applied water around the fire to stop it spreading.
It then took them about 5 to 6 minutes to set up a new foam machine before they started applying foam to the fire, by which time most of the helicopter had already burnt out. The pilot stated that the incident happened very quickly and he did not recall seeing or hearing any cockpit warnings
AAIB Analysis:
Although it was a hot day with calm wind, the helicopter was 276 kg below its maximum takeoff weight so it should have had sufficient performance for the taxiing manoeuvre the pilot undertook. It is possible that the airpath to the centrifugal compressor had accumulated deposits during operation which led to a lower compression rate and a higher temperature operation. This, combined with the hot outside air temperature, could have led to a T4 exceedance, turbine damage and a consequential loss of power, leading to the accident.
However, it is also possible that the T4 exceedance occurred during the post-impact fire and that some deposits were ingested while the engine continued to run on the ground, with the helicopter on its side.
Accident investigation:
 |
|
Sources:
AAIB
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 09-May-2019 17:44 | harro | Added |
| 20-Nov-2023 13:35 | harro | Updated [Other fatalities] |
Corrections or additions? ... Edit this accident description
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