ASN Wikibase Occurrence # 278777
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| Date: | Tuesday 12 November 2019 |
| Time: | 20:08 |
| Type: |  AgustaWestland A109SP |
| Owner/operator: | IHC Health Services Inc |
| Registration: | N271HC |
| MSN: | 22250 |
| Year of manufacture: | 2011 |
| Engine model: | Pratt & Whitney PW207 |
| Fatalities: | Fatalities: 0 / Occupants: 3 |
| Aircraft damage: | Substantial |
| Category: | Accident |
| Location: | Salt Lake City, UT -
 United States of America
|
| Phase: | En route |
| Nature: | Ambulance |
| Departure airport: | Murray Medical Center Helipad, UT (UT11) |
| Spanish Fork, UT | |
| Investigating agency: | NTSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
The crew of the helicopter air ambulance flight departed to pick up a patient in night visual meteorological conditions. While en route to their destination, a flight nurse, who was seated in the left seat and communicating with ground personnel, inadvertently depressed the helicopter’s left anti-torque pedal instead of the foot-activated push-to-talk (PTT) switch to activate the microphone. The helicopter suddenly yawed left about 11°, which the pilot immediately countered and restored straight-and-level flight. The helicopter sustained damage to the tail rotor blades and empennage that was not discovered until several hours later when the accident crew was relieved.
The damage to the blades and empennage was consistent with their making contact, and the flight data suggest this occurred during the first leg of the shift flight as the crew did not experience any other events that would have caused the degree of damage observed. Postaccident examination of the tail rotor gearbox and tail rotor blades did not reveal any anomalies. A performance analysis by the helicopter manufacturer showed that the amount of left pedal applied at the time of the pilot’s yaw recovery exceeded the parameters tested during certification.
The flight nurse seated in the cockpit at the time of the accident normally sat in the rear cabin and was likely not as familiar with the location of the PTT, especially in nighttime lighting conditions.
Probable Cause: The flight nurse’s inadvertent application of left anti-torque pedal during cruise flight, which resulted in a rapid yaw and pitch movement that caused the tail rotor blades to contact the tailboom.
Accident investigation:
 |
|
Sources:
https://data.ntsb.gov/Docket?ProjectID=100590
http://aerossurance.com/helicopters/aw109s-haa-tail-rotor-tailboom/
Location
Media:
A flight nurse reaching for the floor mounted PTT switch resulted in a yaw that exceeded certification requirements. The damage was missed until the next day. https://t.co/AW9h0lSg9p #helicopter #airambulance #flightsafety #aviationsafety pic.twitter.com/Wck5Rg81Lq
— Aerossurance (@Aerossurance) June 11, 2022
Revision history:
| Date/time | Contributor | Updates |
|---|---|---|
| 03-Jun-2022 23:17 | Captain Adam | Added |
| 04-Jun-2022 08:14 | Aerossurance | Updated [Source] |
| 11-Jun-2022 11:34 | Aerossurance | Updated [Source] |
| 11-Jun-2022 11:57 | Aerossurance | Updated [Embed code] |
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