Taupo | Bureau of Aircraft Accidents Archives

On 7 January 2015 a Pacific Aerospace Limited 750XL aeroplane was being used for tandem parachuting (or ‘skydiving’) operations at Taupō aerodrome. During the climb on the fourth flight of the day, the Pratt & Whitney Canada PT6A-34 engine failed suddenly. The 12 parachutists and the pilot baled out of the aeroplane and landed without serious injury. The aeroplane crashed into Lake Taupō and was destroyed.

Probable cause:

The following findings were identified:
- The first compressor turbine blade failed after a fatigue crack, which had begun at the trailing edge, propagated towards the leading edge. The blade finally fractured in tensile overload. The separated blade fragment caused other blades to fracture and the engine to stop.
- The fatigue crack in the trailing edge of the blade was likely initiated by the trailing edge radius having been below the specification for a new blade.
- The P&WC Repair Requirement Document 725009-SRR-001, at the time the blades were overhauled, had generic requirements for trailing edge thickness inspections but did not specify a minimum measurement for the trailing edge radius.
- The higher engine power settings used by the operator since August 2014 were within the flight manual limits. Therefore it was unlikely that the operator’s engine handling policy contributed to the engine failure.
- The operator had maintained the engine in accordance with an approved, alternative maintenance programme, but the registration of the engine into that programme had not been completed. The administrative oversight did not affect the reliability of the engine or contribute to the blade failure.
- It was likely that the maintenance provider had not followed fully the engine manufacturer’s recommended procedure for inspecting the compressor turbine blades. It could not be determined whether the crack might have been present, and potentially detectable, at the most recent borescope inspection.
- The operator had not equipped its pilots with flotation devices to cover the possibility of a ditching or an emergency bale-out over or near water.
- The pilot had demonstrated that he was competent and he had the required ratings. However, it was likely that the operator’s training of the pilot in emergency procedures was inadequate. This contributed to the pilot making a hasty exit from the aeroplane that jeopardized others.

Final Report:

Crash of a Fletcher FU-24-950 near Taupo

Date & Time: May 8, 1995 at 0720 LT

Type of aircraft:

Fletcher FU-24

Operator:

Registration:

ZK-EMB

Flight Phase:

Takeoff (climb)

Flight Type:

Spraying (Agricultural)

Survivors:

Yes

Site:

Plain, Valley

MSN:

252

YOM:

1978

Location:

Taupo

Waikato Regional Council

Country:

New Zealand

Region:

Oceania

Crew on board:

Crew fatalities:

Pax on board:

Pax fatalities:

Other fatalities:

Total fatalities:

Captain / Total flying hours:

332

Captain / Total hours on type:

44.00

Circumstances:

Sole on board, the pilot was engaged in a crop spraying mission in the region of Taupo. Shortly after takeoff, while climbing at low height, the pilot initiated a right turn when the aircraft lost height and crashed in a pasture about 11 km northeast of Taupo. The aircraft was destroyed and the pilot was seriously injured.

Probable cause:

The following findings were reported:
- During a turning manoeuvre at a low height, the aircraft stalled and squashed onto the ground in a wing level attitude, at a high rate of descent,
- The height of the aircraft above the ground at the time afforded the pilot little opportunity for recovery,
- The pilot probably reverted to an unsafe flying practice he had adopted during his earlier training,
- The unsafe practice had been recognised by a previous instructor who, when not successful in correcting it, had discontinued the pilot's training,
- The final instructor had no reason to be concerned about the pilot's flying as he had exhibited no dangerous trends and flew as instructed,
- Had the final instructor been aware of a previous trait of the pilot to perform unsafe manoeuvres he might have been able to correct it,
- The causal factors in this accident were a lack of continuity in training records, pressure the pilot believed he was under to achieve maximum productivity in his flying with a minimum of delay, the pilot's apparent refusal to accept cautions in relation to his ability, and the Fletcher aircraft's performance during the execution of a limit manoeuvre too close to terrain.

Final Report:

Crash of a Fletcher FU-24 in Orakei Korako: 1 killed

Date & Time: Sep 20, 1961 at 1330 LT

Type of aircraft:

Fletcher FU-24

Operator:

Registration:

ZK-BOB

Flight Phase:

Flight

Flight Type:

Spraying (Agricultural)

Survivors:

Site:

Plain, Valley

Schedule:

Te Waro - Te Waro

MSN:

YOM:

1958

Location:

Orakei Korako

Waikato Regional Council

Country:

New Zealand

Region:

Oceania

Crew on board:

Crew fatalities:

Pax on board:

Pax fatalities:

Other fatalities:

Total fatalities:

Captain / Total flying hours:

1260

Captain / Total hours on type:

31.00

Circumstances:

The pilot was a former member of the Royal Canadian Air Force where he had logged 1,260 hours flying in both single and multi-engined aircraft. He had come to New Zealand with the intention of working as an agricultural pilot. He had been employed by James Aviation as a trainee topdressing pilot and had completed 22 hours of supervised productive flying at the time of his death. His total flying in the FU24 was 31 hours. At 1315 on the day of the accident he took over ZK-BOB from another trainee, making three satisfactory sorties without incident and then departed on a fourth. Shortly afterwards the absence of engine noise was noticed by those on the airstrip and the supervising instructor took off immediately on an aerial search and located ZK-BOB, crashed and burning, about 400 metres outside the sowing area. The crash site was 92 metres below the level of the area being topdressed. The plane had cartwheeled, rotating about its normal axis and finishing up 12 metres beyond a decapitated pine sapling. The port outer wing section was found 29 metres from the main wreckage, its tip showing evidence of a severe ground impact at the leading edge. The port inner wing displayed a deep indentation at the leading edge just inboard of the outer wing joint. This indentation extended back to the rear spar. The rear spar had become distorted and had jammed the aileron pulley in a way that would sustain a steep left turn in flight. The entire central portion of the fuselage, including the cockpit, had been consumed by fire. The engine was embedded almost vertically in the ground to a depth of 600 mm. The pilot's body had been thrown from the cockpit by the force of the impact with the ground and was found a short distance away. It was noted immediately at the beginning of the crash investigation that the wreckage lay some 90 metres below the level of the dressing area, and in a place that the aircraft would not have crossed in the course of its sowing operation. Attention was then focused on the deep indentation in the leading edge of the port wing and the associated jamming of the aileron control pulley in a position that would sustain a left turn. There was no object in the wide area around the crash site that could account for this damage. It was established that the pine sapling close to the wreck had been sheared through by the aircraft's propeller. It was suspected that, when flying in the sowing area, the aircraft had hit some obstruction, the damage from which had forced the plane into an irrecoverable steep left turn, or locked the plane into such a turn if it was making the manoeuvre at the time of collision. An intensive search was made in the sowing area to locate some object that could have caused the deep indentation to the port inner wing section. No completely reliable evidence was found, but two trees on the edge of the sowing area showed the sort of damage that an aircraft might inflict. Furthermore, there were trails of superphosphate leading up to those trees and leading away from them in the direction of the valley below. A flying trial showed that a Fletcher making a steep left-hand turn over those trees would pass directly over the crash site. However, no evidence in the form of wreckage or paint particles was found in the trees.
Source: https://aviation-safety.net/wikibase/wiki.php?id=63267

Probable cause:

The investigators concluded that there was evidence to suggest that the aileron controls were jammed through collision with some object while the aircraft was in flight and that jamming resulted in a steep left turn from which a recovery could not be made.