ASN Wikibase Occurrence # 59481
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| Date: | Tuesday 1 August 1989 |
| Time: | 15:22 LT |
| Type: |  Robinson R22 Beta |
| Owner/operator: | Helicarr Consolidated Ltd |
| Registration: | ZK-HYX |
| MSN: | 0666 |
| Year of manufacture: | 1987 |
| Fatalities: | Fatalities: 2 / Occupants: 2 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Whitford Forest, Auckland -
 New Zealand
|
| Phase: | En route |
| Nature: | Private |
| Departure airport: | Ardmore, New Zealand (AMZ) |
| Ardmore, New Zealand (AMZ) | |
| Investigating agency: | TAIC |
| Confidence Rating: |  Accident investigation report completed and information captured |
On August 1, 1989, at about 15:22 local time, a Robinson Beta helicopter, registered in New Zealand as ZK-HYX, crashed near Whitford Forest, New Zealand, after an in-flight separation of the tail boom.
After departing from Ardmore Aerodrome, the pilot had informed Ardmore Tower that he and his passenger were proceeding to Whitford Forest and indicated that the duration of the flight would be about 20 minutes. The private helicopter pilot and passenger were killed, and the helicopter was destroyed. The pilot had accumulated a total of 286 flight hours, 282 of which were in helicopters and 276 in the R22 helicopter.
The pilot had flown a helicopter only twice in the 4 months preceding the accident. The weather at Ardmore Aerodrome, 10 km south-south-west of the accident site at 1500 hours, was reported to be 2 octas cumulus at 3,500 feet, 60 km visibility with haze, winds from 500 at 10 knots.
Subsequent analysis of the weather data suggested that a prevailing northeast wind may have produced "moderate turbulence close the hills with down draughts in the lee of the ridges." It was believed that the flight was conducted at low altitude.
The investigation by the New Zealand Transport Accident Investigation Commission (TAIC) found that the tail boom, vertical and horizontal stabilizers, and the tail rotor assembly were located in the tops of trees 80 to 100 meters from the fuselage. The severe "near vertical" impact of the fuselage on a steep hillside bent the left skid of ZK-HYX upwards, and splayed the right skid outwards. The under structure and engine were forced upwards and the mast assembly was fractured at its base and was bent to the left. Both main rotor blades remained attached to the rotor head. The TAIC reported that the damage to the blades was characteristic of low rotational energy at the time of ground impact. One main rotor blade had revolved 180° in its pitch bearing, and was bent "upwards" when positioned correctly in relation to the opposite blade, which was bent "downwards." The TAIC reported that both pitch change links had bent before failure. It also reported that there was no significant evidence of mast bumping but the rotor mast was bent slightly at the top, and the metal droop stops (that limit the downward movement of the main rotor blades) had sheared in overload. The examination found no defect in the main rotor head or blades that was considered to have contributed to the cause of the accident.
The TAIC's examination found that a main rotor blade had struck the tail boom dislodging the anti-collision beacon and caused the aft section of tail boom and driveshaft assembly to separate.
Severe damage to the inboard end of the middle section of the tail boom and matching paint smears on the main rotor blades indicated that this section had been struck by the blades while the helicopter was still in flight. The TAIC reported that is was evident that at the time of separation, the tail rotor was being driven with considerable rotational energy. Heavy scoring was on the internal skin in the area of the fuselage/tail boom attachment indicating continued rotation of the transmission drive when the strike occurred. Both tail rotor blades were dented over the final 125 mm of their outboard ends. The TAIC found that the relative symmetry of the damage areas on each blade and the severity of denting, with the absence of "rotational" marking, suggested that the outer portion of the tail rotor had struck a branch or tree trunk.
The TAIC reported that no evidence suggested that the cyclic, collective, or tail rotor controls had been obstructed in any way, and established continuity of these control systems. The lower engine compartment was substantially damaged on impact. The carburetor bowl was broken off but both floats were intact. The fuel and engine oil filters were free of contamination, and the engine sump contained an ample supply of oil. The main and auxiliary fuel tanks were ruptured; however, a quantity of fuel remained in the line to the fue
Accident investigation:
 |
|
Sources:
1. https://taic.org.nz/inquiries?SkinSrc=[G]skins/taicAviation/skin_aviation
2. http://www.griffin-helicopters.co.uk/accidentdetails.aspx?accidentkey=42897
3. http://www.libertyhelicopters.co.uk/NTSB_Special%20Report/NTSB_R22Reports/WhitfordForest_NZ.htm
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 10-Apr-2009 01:24 | XLerate | Added |
| 22-Dec-2011 16:50 | Dr. John Smith | Updated [Cn, Operator, Phase, Nature, Departure airport, Destination airport, Source, Damage, Narrative] |
| 22-Dec-2011 16:59 | Dr. John Smith | Updated [Time, Source, Narrative] |
| 19-Sep-2016 18:59 | Dr.John Smith | Updated [Operator, Narrative] |
| 19-Sep-2016 19:00 | Dr.John Smith | Updated [Location] |
| 15-Sep-2020 01:51 | Ron Averes | Updated [Location] |
| 23-Sep-2021 20:46 | Ron Averes | Updated [Location] |
| 05-Mar-2022 01:58 | Ron Averes | Updated [Aircraft type] |
Corrections or additions? ... Edit this accident description
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