ASN Wikibase Occurrence # 74543
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| Date: | Thursday 27 May 2010 |
| Time: | 15:20 LT |
| Type: |  Robinson R22 Beta II |
| Owner/operator: | Heli Sitterdorf AG |
| Registration: | HB-ZHB |
| MSN: | 3984 |
| Year of manufacture: | 2005 |
| Fatalities: | Fatalities: 0 / Occupants: 2 |
| Aircraft damage: | Destroyed |
| Location: | Rütistrasse, Henau, near Auzelgli, Gemeinde Uzwil/SG -
 Switzerland
|
| Phase: | Manoeuvring (airshow, firefighting, ag.ops.) |
| Nature: | Training |
| Departure airport: | Sitterdorf Airport (LSZV) |
| Sitterdorf Airport (LSZV) | |
| Investigating agency: | BFU Switz. |
| Confidence Rating: |  Accident investigation report completed and information captured |
On 27 May 2010, shortly after 15:00, the Robinson R22 Beta II helicopter, registration HB-ZHB, took off from Sitterdorf aerodrome. During the departure in a southerly direction, the crew had to avoid two birds during the climb. The trainee pilot's reaction and the evasive manoeuvre were adequate, according to flight instructor A. The helicopter passed the South Sector of Sitterdorf aerodrome and then continued to fly in a south-south-westerly direction. To the west of Gossau, flight instructor A specified a field for an off-airport landing. The trainee pilot commenced the reconnaissance of the designated landing site and then started his approach. The approach was too high and furthermore an agricultural vehicle was crossing the field. Thus flight instructor A ordered a go-around. This took place at approximately 15:15.
The crew then followed the A1 motorway in a westerly direction and climbed to approximately 3000 ft QNH. During horizontal cruise, flight instructor A throttled back a little using the twist-grip, in order to cause a low RPM situation as well as the corresponding warning. The trainee pilot reacted promptly and with the correct measures.
Then – the helicopter was now to the north of Niederuzwil – flight instructor A sighted an appropriate field. This field had often served him in the past for various exercises, especially autorotations. He asked the trainee pilot whether he was ready for an autorotation exercise, and the latter replied in the affirmative.
Flight instructor A then turned on the carburettor heating, got ready at the controls and closed the twist-grip. The reaction of the trainee pilot – collective pitch control (collective) down and cyclic control (cyclic) slightly back – was correct. To the question from flight instructor A about where the trainee pilot intended to land, the trainee pilot mentioned the same field which flight instructor A had already sighted. The trainee pilot had never performed an approach to this field before.
With a S-turn, i.e. a left turn followed by a right turn, the trainee pilot reduced excessive height. After completing the turns, the final approach ensued, in a north-westerly direction, with the airspeed and rotor speed within the desired range. Flight instructor A turned off the carburettor heating. He now realised that the trainee pilot was not transitioning to the flare. Such a flare is essential on approaching the terrain in an autorotative descent; pulling back the cyclic reduces both the rate of descent and the forward speed. Flight instructor A described this phase as follows: "Normally, trainees tend to carry out a high flare. In this case, nothing happened."
Flight instructor A took hold of the controls and assumed control of the helicopter. In his judgement the helicopter was already too close to the ground to be able to initiate a normal flare, as such a flare would have led to an impact between the ground and the tail boom. According to the flight instructor A's assessment, it was also too late to initiate a go-around, he therefore concentrated on making contact with the ground in as controlled a manner as possible.
Shortly before or during contact with the ground, he pulled the collective. It could not be ascertained whether and when flight instructor A opened the twist-grip again. The helicopter impacted the field in an approximately horizontal attitude with forward speed. The landing gear was deformed laterally by the high impact forces and the underside of the fuselage also left distinct traces of impact. The helicopter then tipped forward, the rotor blades struck the ground and the tail boom became detached. After flipping over once or twice the helicopter came to lie on its right side and slid in this position a few metres further before it came to a standstill, destroyed.
Flight instructor A, who sustained a slight injury to the head, was able to exit the wreckage unaided and helped the trainee pilot, who was also slightly injured, to exit the helicopter. Both crew members did not wear a helmet. Since fuel was leaking, flight instructor A asked the trainee pilot to close the fuel valve. The trainee pilot did so. Together with an eyewitness who rushed to give assistance, the crew then righted the helicopter to prevent further leakage of fuel, oil and lubricants.
The rescue team, alerted by the eyewitnesses, arrived at the scene approximately fifteen minutes after the accident. Flight instructor A and the trainee pilot were taken to hospital for outpatient treatment. The investigation was started at the scene of the accident on the same day, in cooperation with the St. Gallen cantonal police. The topmost layer of soil at the final position of the helicopter had to be removed and disposed of because of the leakage of fuel, oil and lubricants.
Accident investigation:
 |
|
Sources:
1. http://www.sust.admin.ch/pdfs/AV-berichte/2114_e.pdf
2. http://www.feuerwehr-schweiz.ch/index.php?module=Pagesetter&func=viewpub&tid=4&pid=1938
3. http://www.news.ch/Zwei+Verletzte+bei+Helikopter+Absturz/441878/detail.htm
4. http://www.news.ch/suche/default.aspx?c=galerien&ID=1173&picID=1
5. http://www.20min.ch/schweiz/ostschweiz/story/Heli-crasht-bei-Henau---zwei-Verletzte-13934451
6. http://www.tagblatt.ch/aktuell/polizeinews/Zwei-Verletzte-bei-Helikopterabsturz;art675,1551186
7. http://www.airliners.net/photos/airliners/7/5/9/1332957.jpg (photo)
8. http://www.swissheli.com/history/hb-zhb.htm
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 28-May-2010 06:48 | Tetra | Added |
| 28-May-2010 07:14 | RobertMB | Updated [Time, Aircraft type, Cn, Location, Departure airport, Destination airport, Source] |
| 28-May-2010 07:24 | RobertMB | Updated [Source] |
| 06-Oct-2016 13:23 | Dr.John Smith | Updated [Location, Departure airport, Destination airport, Source, Narrative] |
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