HEMS H145 Bird Strike (HB-ZQJ)
On 24 March 2021 Airbus H145 air ambulance HB-ZQJ of Schweizerische Luft-Ambulanz was damaged by a bird strike in the cruise. The 1.3 kg bird penetrated the lower cockpit window at rudder pedal level.
Bird Strike Damage to to HEMS Airbus H145 HB-ZQJ (Credit: via SUST)
The Swiss Safety Investigation Board (SUST) issued their safety investigation report in French on 10 March 2024.
The Flight
The helicopter was undertaking a night patient transfer from Yverdon-les-Bains Hospital to Vaudois University Hospital in Lausanne (both hospitals have elevated helipads). On board were one pilot, two medical personnel and the patient.
At 22:01 Local Time, 5 minutes into the flight, the helicopter was in the cruise at c 1000 ft AGL on autopilot when the bird strike occurred over Bretigny-sur-Morrens.
Flight Path of HEMS Airbus H145 HB-ZQJ (Credit: via SUST)
The pilot felt a pain in his right leg having been impacted by remains of the bird…
[The pilot] took manual control of the helicopter, reduced speed and ensured that the power and airworthiness of the helicopter were not affected by the impact.
Despite entry at foot height the pilot was also hit in the head by debris. The pilot’s helmet “had numerous stains from the bird.”
The helicopter diverted to their base at Lausanne.
SUST Analysis and Conclusions
SUST do not report the bird species but explain:
The impact of the bird surprised the crew while the helicopter was cruising at night. It was therefore not possible to detect the presence of birds and attempt an avoidance maneuver.
The shattering of the canopy with the penetration of the bird and the projection of the remains into the dark cabin must have caused a stressful situation which was well managed by the pilot.
…the decision to divert to home base was appropriate.
Of note is:
The pilot’s equipment including helmet, robust suit and mountain boots contributed to the pilot’s physical integrity.
Aerossurance customers who operate the H145 fly HEMS, helicopter hoist and military missions with the helicopter and operate with a similar ‘aircrew equipment assembly’ standard.
Design & Certification Standards
The current H145 lower cockpit windows are 2mm acrylic, reinforced round the edges. The current windshields are 6mm acrylic.
The H145 is a derivative of the original BK117 (the four main rotor blade H145 is the BK117D2 and the five bladed H145 the BK117D3).
While, as per the Changed Product Rule (Part-21.A.101), the certification basis for some changed H145 elements are recent amendments of CS-29, the EASA H145 Type Certificate Data Sheet (TCDS) states that otherwise FAR 29 Amdt. 40 from 1996 applies for all the other applicable requirements, except for three reversion to FAR 29 Amdt. 16 from 1978, significantly including “FAR 29.631 (for cockpit windscreens only)“.
FAR 29 only introduced a bird strike requirement at FAR 29 Amdt. 40 in 1996:
The rotorcraft must be designed to ensure capability of continued safe flight and landing (for Category A) or safe landing (for Category B) after impact with a 2.2-lb (1.0 kg) bird when the velocity of the rotorcraft (relative to the bird along the flight path of the rotorcraft) is equal to VNE or VH (whichever is the lesser) at altitudes up to 8,000 feet. Compliance must be shown by tests or by analysis based on tests carried out on sufficiently representative structures of similar design.
So the H145 cockpit windscreen was not required to meet the 1996 requirement.
Future Developments & Past History
SUST note that Airbus are developing a product upgrade, though that is not yet certified at the time they issued their report. It is not clear if that is just a new lower cockpit window or new windshield too.
Ironically the BK117C1C was a derivative of the BK117C1 specifically developed, after an extended on/off/on certification programme, to meet the then applicable UK CAA requirements and the resulting additional national requirements:
Front windshields of increased thickness, part no. 117-810051, are to be fitted. A reinforced crest cowling part no. 117-810041, which protects the hydraulic pack mounted on the cabin roof, is also to be installed.
These components have been demonstrated by tests to withstand impact with a two-pound bird under all required conditions.
Safety Resources
The European Safety Promotion Network Rotorcraft (ESPN-R) has a helicopter safety discussion group on LinkedIn. You may also find these Aerossurance articles of interest:
- Safety Lessons from a Fatal Helicopter Bird Strike: A fatal accident occurred on 4 Jan 2009 involving Sikorsky S-76C++ N748P of PHI that highlighted a range safety lessons. We also discuss current activity on enhancing bird strike requirements.
- USAF HH-60G Downed by Geese in Norfolk, 7 January 2014
- Swedish Military NOE Helicopter Bird Strike
- Power of Prediction: Foresight and Flocking Birds looks at how a double engine loss due to striking Canada Geese had been predicted 8 years before the US Airways Flight 1549 ditching in the Hudson (which was just days after the Louisiana helicopter accident).
- Final Report Issued on 2008 B737 Bird Strike Accident in Rome
- NTSB Recommendations on JT15D Failure to Meet Certification Bird Strike Requirements
- USAF T-38C Downed by Bird Strike
- AS350B3/H125 Bird Strike with Red Kite
- Big Bustard Busts Blade: Propeller Blade Failure After Bird Strike
- AW169 Birdstrike with a Turkey Vulture
- Dusk Duck: Birdstrike During Air Ambulance Flight
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