AW109SP Helicopter Air Ambulance Mountain Landing Accident Utah (Intermountain Life Flight N631HC)
On 8 October 2024, Leonardo AW109SP GrandNew N631HC, a helicopter air ambulance of Intermountain Life Flight, landed hard during a night call out to attend a patient at >10,000 ft amsl in a mountainous region of Utah.
Intermountain Life Flight Leonardo Helicopters AW109SP GrandNew N631HC (Credit: Operator via NTSB)
The landing gear collapsed and the belly was damaged. One of the three occupants suffered a minor injury.
The US National Transportation Safety Board (NTSB) issued a sparse safety investigation report on 8 April 2025. The report is mostly based on the pilot’s detailed statement.
The Accident
At about 03:30 the pilot, who was going to operate the aircraft single pilot, was called by Comm-Center (CC) asking if he would accept a flight into the High Uintahs wilderness area “for a patient in the woods”, noting that the Summit SAR team, a ground SAR team was still to reach the casualty.
The pilot was told that another operator, AirMed “had turned this flight down due to smoke and visibility” and the Department of Public Safety (DPS) “did not want to respond at this time”.
This appears to be case of helicopter shopping where the tasking agency calls several operators. A positive is that the pilot was told others had declined, providing context to inform their decision making and encourage critical thinking The downside is this can put pressure on the pilot as they may perceive they are the ‘last hope’ for a casualty until dawn.
The pilot, who had 5127 hours total time, 1105 hours at night and 170 on type, reported that:
Conditions were some clouds in the sky, Zero moon illumination as the moon had set at approximately 2207hrs.
After receiving the initial details he examined ForeFlight, and…
…looked at fuel requirements and not knowing if I would need to search for their location elected to add fuel to ensure I had a loiter time if needed. I knew that minimum fuel to complete the flight from the scene area to IMED in Murray, Utah was 150kg which included my reserve.
The crew went to the aircraft, and the pilot completed a pre-flight risk assessment selecting:
- Night Shift
- Flight between 2-6 am
- Unfamiliar destination
- Technical flight
The first three are self evident but its unclear what the last relates to.
I added my fuel and added more than I had planned by mistake (due to I’ve never topped off the aircraft at Logan and when at IMED it is usually 410 when fuel is about to spill out the fuel port).
Prudently the pilot…
…mentioned to the crew about the possibility of reduced visibility and that we would take it slow with that consideration and then we departed.
Enroute to the destination it was brought up in discussion why we were being called and I mentioned that Airmed had turned down for visibility (thought I had mentioned that before), DPS said that they would wait till sunrise.
The next comment in the pilot’s statement indicates that by this point of the flight the crew no longer expected to search for the casualty, presumably because the ground SAR party had now reached them and passed a landing site location.
It was mentioned that the altitude of the LZ was approximately at 9300’. I noted the temperature @ 11º since we were cruising at 9300 and about 15 minutes out and then pulled up the HOGE chart noting that if all worked as planned I should be close to weight at arrival including the need to orbit while the SAR completed making contact.
Crucially the…
…LZ [was] changed to Elizabeth Ridge at about 5 minutes out which was at apparently at 10,276’.
So not only was the helicopter carrying excess fuel for a search that was no longer required but the landing site was almost 1,000 ft higher than expected.
Upon arrival over Elizabeth Ridge contact was made with the ground SAR team. The helicopter first overflew the site a c300-400 ft and c50-60 knots.
The LZ was well lighted by the SAR teams vehicles so over all we had good visibility on it, winds were out of the west, visibility was 6+.
I mentioned that for the second pass I would slow some more and lower to get a feel for the aircraft and a better view of the LZ which was for the most part a dirt road intersection open on both side with some smaller trees around and also surrounded by taller trees, we also started the before landing check at this time.
I felt that although you could not do a shallow approach the area was big enough to land a couple of Blackhawks or say at least 340’ L by 100’ wide (probably wider) where the intersection was and I did not pickup on the fact that the road as it went west past the small intersection did curve to the right.
The second pass confirmed to the pilot that the site was large enough. The pilot noted the location of the taller trees on the approach path and the possibility of brown-out.
While he states “it seemed the aircraft was handling OK” he then states:
…I do not remember noting the torque and being at 40 knots, I…was concentrating outside the aircraft due to the lack of moon.
The pilot does not mention the use of a Night Vision Imaging Systems (NVIS), though the Form 6120 accident report form states the two medical personnel had Night Vision Googles (NVGs) but the form’s NVG tick box is not selected for the pilot (we suspect an oversight completing the form).
The pilot added that the trees and vehicles surrounding the landing site restricted his options.
We would observe however that the vehicles could have been instructed to move…but even more so they were also potentially a way to move the casualty to a better, lower landing site. The original site at 9,300 ft was apparently a meadow that the hikers themselves had passed earlier in the day and suggested to the ground SAR party before the team selected the dirt road intersection. The helicopter had the fuel to wait and there is no evidence of clinical urgency,
We’ve previously written about another a more extreme case where the ground party selected a poor site for an EMS helicopter to land: Air Ambulance Night Wirestrike at Poorly Chosen Landing Site
On approach the SAR team shutdown their lights, we slowed the aircraft below 50 knots and then Troy [one of the two medical crew, most likely sat in the front left seat] opened his door to clear the aircraft and watch for dust.
As we were approaching he was clearing me of the tree’s, called to move further forward and right (I believe) and then he felt that dust was building up, it was at this time he called for me to hold and I attempted to slow the aircraft, but due to weight and altitude I got a High Torque call out and noted 111%, I thought about a go-around but saw trees in my departure path so I knew I was below the trees (or a few of the taller ones) and at this time announced that we were not able to do a go-around and we would need to land as I could feel the sluggishness of the helicopter.
As we approached the ground I pulled in collective and at this time the nose started to turn right slowly and I could not correct ultimately facing about 90º to the right of our approach heading.
NTSB Analysis / Summary and Our Observations
Firstly NTSB state misleadingly:
The pilot of the helicopter reported that he mistakenly added more fuel than was required to complete a mountainous terrain, confined area landing at an elevation of 10,276 ft msl.
The pilot had loaded more fuel than he intended but he deliberately planned to carry more fuel than ultimately needed, specifically to allow for a search that was at the time expected.
The landing site was also changed during the flight and while the pilot may have made assumptions about what elevation the casualty was at before departure, the 10,276 ft msl site was only notified in flight, 5 minutes before arrival.
During his approach to the landing area, the helicopter descended below the tree line preventing a go around.
As the helicopter descended, the pilot increased collective to add power, but he observed a high torque indication of 111% and he felt the “sluggish” performance of the helicopter. The tail rotor effectiveness diminished, an uncommanded right yaw ensued, and the helicopter landed hard, which resulted in substantial damage to the lower fuselage.
The NTSB then go onto to state (our emphasis added) in the report we downloaded on 17 May 2025:
The pilot reported that there were no preaccident mechanical failures or malfunctions with the powered glider that would have precluded normal operation.
We have all made cut and paste errors but its surprising this was not picked up by the Board when they authorised the release of this report as this was in a distinctively different font / size:
As we have repeatedly pointed out in our past US helicopter air ambulance accident case studies, in 2017 the FAA amended Part 135 so that such operators have to comply with a Flight Data Monitoring (FDM) System requirement, FAR 135.607.
FAA AC 135-14B Helicopter Air Ambulance (HAA) Operations explains that the system…
…should record digital or analog raw data, images, cockpit voice or ambient audio recordings or any combinations thereof which ideally yield at least the following flight information: • Location; • Altitude; • Heading; • Speeds (airspeed and groundspeed); • Pitch, yaw, and roll attitudes and rate of change; • Engine parameters; • Main rotor RPM; • Ambient acoustic data; • Radio ambient audio; and • Any other parameter the operator deems necessary (e.g., high definition video recording looking forward including instrument panel and forward cockpit windshield view, intercommunications system (intercom) between pilot and medical crew, communications with air traffic control (ATC), OCS, base operations, first responders at scene, hospital, etc.)
So safety investigators would have had ready access to extensive data to evaluate the approach and also determine the effectiveness of the FDM program in routinely monitoring mountain approaches and providing constructive feedback to crews. Again this option was not taken up by NTSB.
More remarkable is that the NTSB, while continuing advocate the value of FDM but not themselves availing themselves of the data, do also highlight that the FAA “does not require that operators use the recorders and the data collected”!
As a final observation from us: A public inquiry chaired by Anthony Hidden QC investigated the 1988 Clapham Junction rail accident. In his report, known as the Hidden Report, he commented:
There is almost no human action or decision that cannot be made to look flawed and less sensible in the misleading light of hindsight.
It is essential that the critic should keep himself constantly aware of that fact.
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:
- Korean SAR S-76B Mountain Rescue Accident 2020
- That Others May Live – Inadvertent IMC & The Value of Flight Data Monitoring
- HEMS Air Ambulance Landing Site Slide
- Multi-Tasking Managers & Deficient Operational Control: Low Viz AS350B3 Take-Off Accident
- HEMS AW109S Collided With Radio Mast During Night Flight
- Air Ambulance Helicopter Struck Ground During Go-Around after NVIS Inadvertent IMC Entry
- HEMS A109S Night Loss of Control Inflight
- Air Ambulance A109S Spatial Disorientation in Night IMC
- HEMS S-76C+ Night Approach LOC-I Incident
- Dusk Duck: Birdstrike During Air Ambulance Flight
- Air Ambulance Night Wirestrike at Poorly Chosen Landing Site
- Managing Interruptions: HEMS Call-Out During Engine Rinse
- Air Ambulance Helicopter Downed by Fencing FOD
- Ambulance / Air Ambulance Collision
- Austrian Police EC135P2+ Impacted Glassy Lake
- US Fatal Night HEMS Accident: Self-Induced Pressure & Inadequate Oversight
- EC135 Air Ambulance CFIT when Pilot Distracted Correcting Tech Log Errors
- AAIB Report on Glasgow Police EC135 Clutha Helicopter Accident
- EC135P2+ Loss of NR Control During N2 Adjustment Flight
- Maintenance Misdiagnosis Precursor to EC135T2 Tail Rotor Control Failure
- Misassembled Anti-Torque Pedals Cause EC135 Accident
- Night CHC HEMS BK117 Loss of Control
- Norwegian HEMS Landing Wirestrike
- HEMS Pilot Seizure While Rotor-Running
- Air Ambulance EC135 Loss of Control & Main Rotor / Engine Overspeeds
- EC135P2+ Air Ambulance Fatal Accident Mississippi 10 March 2025
- UPDATE 25 May 2025: CHC Sikorsky S-92A Seat Slide Surprise(s)
See also:
- EHEST Leaflet HE 3 Helicopter Off Airfield Landing Sites Operations
- EHEST Leaflet HE 7 Techniques for Helicopter Operations in Hilly or Mountainous Terrain
UPDATE 29 May 2025: The Swiss Helicopter Association (SHA) has issued a 148-page Mountain Flying Handbook
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