ASN Wikibase Occurrence # 140478
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| Date: | Thursday 8 December 1994 |
| Time: | 14:05 LT |
| Type: |  Robinson R44 |
| Owner/operator: | Luftfahrt-Gesellschaft-Mannheim |
| Registration: | D-HPHS |
| MSN: | 0107 |
| Year of manufacture: | 1994 |
| Fatalities: | Fatalities: 2 / Occupants: 2 |
| Aircraft damage: | Destroyed |
| Category: | Accident |
| Location: | Speyer -
 Germany
|
| Phase: | En route |
| Nature: | Training |
| Departure airport: | |
| Investigating agency: | BFU |
| Confidence Rating: |  Information verified through data from accident investigation authorities |
On December 8, 1994, about 14:05 local time, a Robinson R44 helicopter, registered in Germany as D-HPHS and operated by Luftfahrt-Gesellschaft-Mannheim, broke apart during an instructional flight about 2,000 feet agl, near Speyer, Germany. The flight was intended to be a continuation of the second pilot's R44 type-rating training. 38 Witnesses near the accident site reported that they heard a loud noise and observed the helicopter falling to the ground with parts of the helicopter separating from the structure as it fell. The instructor pilot and student were killed, and the helicopter was destroyed. The instructor had accumulated 2,885 pilot flight hours in helicopters, 123 of which were in the R44. The R44 student held a commercial pilot certificate (airplane and helicopter) with flight time in the smaller, but similar, Robinson R22 and several hours in the R44. The NTSB and the FAA were participating in the German Accidents Investigation Bureau's continuing investigation of the accident.
Radar data and the history of flight indicate that the helicopter was cruising about 80 knots (nautical miles per hour) before the accident. The main wreckage (cockpit, skid assembly, and engine) came to rest inverted on level ground. The tail boom had separated from the fuselage, and pieces were located 1,400 feet north of the main wreckage. The main rotor mast and rotor assembly remained attached to the transmission assembly. One main rotor blade had broken chord-wise, approximately 2 feet from the root, and the outer portion of the blade was located about 1,200 feet south of the main wreckage.
Examination of the wreckage revealed that a main rotor blade had struck the front cockpit structure of the helicopter and that the other main rotor blade had struck the second tail boom bay causing the tail boom in the fourth tail boom bay aft of the fuselage to separate. One of the main rotor blades exhibited scoring that matched the windshield attachment screws of the centre support in the nose of the fuselage. The other main rotor blade exhibited scoring that matched a row of similarly scored rivets on the left side of the tail boom.
One main rotor blade was fractured about 2 feet from the blade horn and was found 1,400 feet from where the fuselage came to rest. The other main rotor blade exhibited severe bending and twisting, and was fractured in several places. Examination of the tail rotor drive assembly showed no indications of pre-impact failure.
The main rotor gear box (transmission), main rotor mast, and main rotor assembly were examined. The main rotor shaft exhibited evidence of mast bumping but no evidence of an initiating material failure was found. The evidence indicates that the mast bumping occurred secondary to the main rotor blades travelling beyond their normal flapping range. The transmission upper cap and entire mast assembly were integral to the transmission and helicopter structure. Both sides of the upper swash plate were fractured at the outer arms, and the corresponding pitch change links were also fractured. Examination of the recovered pieces of pitch change links indicated overload failures. The structural damage of the Plexiglas and cockpit structure indicated low blade momentum during the in-flight strike. An instability of the main rotor, rocking of the mast, and extreme pitch divergence of at least one of the main rotor blades appeared to precede all of the fractures of the main rotor flight control system. The reason for the main rotor pitch divergence has not been determined.
Witnesses near the accident site reported that they heard a loud noise and observed the helicopter falling to the ground with parts of the helicopter separating from the structure as it fell. (2 killed, aircraft written off)
At least three German-registered Robinson R44s - D-HTOP, D-HPHS, and D-HFSD - were lost in circumstances similar to the above, and the NTSB report confirmed that there were a near-identical problem with the main rotor in all three cases.
Accident investigation:
 |
|
Sources:
1. http://www.helionline.net/templates/sites/casualties.html
2. http://www.rotorshop.com/sir9603.pdf
3. http://www.libertyhelicopters.co.uk/NTSB_Special%20Report/NTSB_R44Reports/Hanover_Germany.htm
4. https://www.ntsb.gov/_layouts/ntsb.recsearch/Recommendation.aspx?Rec=A-95-001
5. NTSB Accident Ref DCA95RA005
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 18-Dec-2011 20:14 | Dr. John Smith | Added |
| 19-Dec-2011 09:14 | Dr. John Smith | Updated [Narrative] |
| 19-Aug-2016 18:06 | Dr.John Smith | Updated [Location, Source, Narrative] |
| 12-Oct-2018 13:50 | Dr.John Smith | Updated [Operator, Source, Narrative] |
| 19-Nov-2018 19:11 | TB | Updated [Operator, Location, Narrative] |
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