Windward’s Wayward Rain Pants Down an H500: Loose Article Hazards

Windward’s Wayward Rain Pants Down a Hughes H500 in Hawaii (N690WA): Loose Article Hazards

On 20 February 2024 Windward Aviation Hughes 500 (369D) N690WA made a forced landing on Maui, Hawaii after a loss of tail rotor drive. 

Windward Hughes 500 N690WA After Forced Landing (Credit: Safecom.gov)

The helicopter was charted by the National Parks Service (NPS). 

On 2 December 2024 the US National Transportation Safety Board (NTSB) issued their final report.  NTSB explain that:

The pilot reported that after landing at a remote landing zone (LZ) to pick up a single passenger, the passenger loaded their gear in the aft right seat and secured it with a seatbelt.

The pilot sat in the front left seat.  The helicopter was being operated ‘open door’. 

While enroute, the occupants heard a “loud and violent bang”, helicopter yawed to the right and vibrations ensued.

The pilot looked back at the tail rotor, saw it was spinning freely, and confirmed the tail rotor drive train had failed.

The pilot decided to perform an autorotation into an open field in the Palikea flats area of the Haleakalā National Park.  He told the NTSB:

I rolled the throttle back to idle when it was confirmed I could reach a desired spot. I was unsure of how level the flats were and the area is known to be muddy/boggy. I decided it would be best to have as little ground run as possible so I tried to slow the bird in the flare as much as possible. I leveled out and pulled but didn’t have a whole lot of energy. I first contacted slightly aft left. rocked forward a little and settled into a final resting spot with no visible run on: making it feel like a bounce and settle or like a rough hovering auto – I guess would be the best way to describe it.

After this skillful landing, which resulted in no injuries or further aircraft damage, the pilot examined the aircraft.  The Tail Rotor Drive Shaft was severed:

Fractured TRDS of Windward Hughes 500 N690WA (Credit: FAA via NTSB)

There was impact damage visible on the horizontal stabiliser:

Horizontal Stabiliser Impact Damage Windward Hughes 500 N690WA (Credit: FAA via NTSB)

It was noticed that the passenger’s rain pants were missing from the aft right seat, where they had been secured to a back pack along side a strimmer and other equipment, with external load equipment left stowed unrestrained on the floor. 

Items Stowed on Rear Seats and Unrestrained on the Floor of Windward Hughes 500 N690WA (Credit: Safecom.gov)

It was concluded the clothing had…

…exited the helicopter and impacted the tail rotor resulting in substantial damage to the fuselage, tail boom, horizontal stabilizer and tail rotor assembly and gearbox.

The NTSB Probable Cause was:

The pilot’s failure to ensure the passenger’s gear was properly secured before departure.

The NTSB make no safety recommendations but has previously issued a safety alert All Secure, All Clear – Be vigilant regarding accountability and security of items (SA-26)

However the NPS’s own safety investigation decided that…

…doors on should be the standard configuration for helicopter operations. Exceptions to the standard configuration should be included in the appropriate operational risk assessments, briefed, and approved at the appropriate levels. Risk mitigation factors for doors off should address policies and procedures for the proper security of personnel and equipment, and if necessary, the requirement for secondary restraints.

Open door air tour passenger flights were challenged after a fatal 2018 accident in the East River, NY:  FlyNYON knew of safety concerns before fatal doors-off flight (see also: FlyNYON legal saga comes to a close, more than six years after fatal flight killed five).

Our Safety Observations on the Hazards of Loose Articles – A Series of Flight Safety Case Studies:

Loose Articles Lost from the Cabin

The H500 RFM states the following sensible precautions for open door flights:

Note that there is no mention of allowing any unsecured stowage in the cabin.

In 2022 we covered a case study Loose Clothing Downs Marijuana Survey Helicopter, involving Bell 206L3 N27TK of Helico Sonoma .  This had a verify similar outcome, although it involved the coat of a passenger sat in the cabin.  Again there was no NTSB safety recommendations, but the operator sensibly recommended in their accident report form:

Avoid door-off operation with passenger occupied seats where the pilot can not directly observe the activities of the passenger.

The NZCAA has issued a safety alert on loose articles.  This was reported by the press to be after a specific fatal accident (Hughes 369D ZK-HOJ 18 Oct 2018) were witnesses reported seeing clothing fall from the helicopter after a door came open.  These became wrapped around the tail rotor, causing the death of the three occupants.  That helicopter that was on contract to the NZ Department of Conservation (DOC).  This accident in New Zealand highlights how lucky Windward & USFS were.  The subsequent NZ TAIC safety investigation found…

…it very likely that the left-rear door opened as a result of observed wear in the left-rear door-latch mechanism and the non-specific door-latch maintenance requirements, and that this door opening initiated the accident sequence…[as]  it is virtually certain that the cargo items [in the cabin] had not been properly secured with a seat belt or other restraining device.. 

TAIC also identified this ‘safety issue’:

Pilots who do not fully appreciate this risk may consider situations where doors open in flight to be normal. This can lead to an under-reporting of such events, inadequate investigations of the causes and an increase in the risk of accidents occurring.

After this accident, reports of H500 doors opening in flight increased 12 fold in New Zealand…

Underlying the risk of doors coming open in flight, on 16 January 2025 the Australian Transport Safety Bureau (ATSB) release an ‘occurrence brief‘ on an AS350B2 baggage bay door opening in flight on 3 December 2024 and subsquently a large portion falling from the aircraft.

The [regular] passenger who closed the cargo door prior to departure from the lighthouse later advised the operator that they had closed and latched the door, however the latch felt looser compared to the helicopter normally used.

After the incident:

The operator has replaced the damaged door with a forward‑hinged door and will be installing a cargo door warning light in each of its AS350 helicopters.

The NZCAA alert points to a Robinson Helicopter safety video:

The loss of items overboard can be also be fatal, as we discussed in our 2017 case study: Tool Bag Takes Out Tail Rotor: Fatal AS350B2 Accident, Tweed, Ontario.  In that case four people died when a tool bag came loose from an external work platform and struck the tail rotor of AS350B2 C-GOHS of Hydro One Networks.  The Transportation Safety Board of Canada (TSB) issued a safety advisory after that accident:

Cargo must be adequately secured at all times, to prevent it from shifting or departing the helicopter during flight.

Even heavy equipment can depart a cabin.  NTSB has previously published their report into a non-fatal accident in Hawaii on 4 October 2016  with Hughes (MD) 500 / 369E N311VT of Volcano Helicopters (photos) where external load equipment had also been left loose on the cabin floor:

The commercial pilot reported that, after completing an external cargo lift operation, he landed at a remote location to jettison the lift cable and to board the two ground workers for a ferry flight back to their home base.

Shortly after liftoff, the pilot felt a moderate aberration in the cyclic flight control, followed by a significant vertical vibration. The pilot subsequently observed that the main rotor (MR) blade track had a substantial blade spread. Subsequently, the pilot conducted a forced emergency landing…

…examination of the helicopter revealed that one MR blade was missing about 9 inches of its blade tip, consistent with impact with an object of substantial mass…

The pilot reported that he released the lift cable before the flight…[and]…the ground crew placed the coiled cable in the rear compartment that had no doors.

…based on the damage to the MR blades, it is likely that the cable exited the helicopter during liftoff and subsequently impacted the MR, which resulted in the separation of an MR blade tip and the vertical vibration of the helicopter.

Loose Articles in the Cockpit

Even loose articles that aren’t lost overboard can be fatal.  In July 2023 we discussed a fatal CH-47 accident where an Electronic Flight Bag (EFB) iPad became jammed with journalist Elan Head: Dropped iPad implicated in fatal Rotak Chinook helicopter crash

Andy Evans, director of the aviation safety consultancy Aerossurance, said that while operators are generally required to conduct risk assessments before adopting EFBs, there is often not an explicit requirement to consider the risk of the EFB as a loose object.

“Hopefully this accident will prompt operators to have a long hard look at all possible loose articles in cockpits and robustly securing valuable tools and sources of situational awareness like EFBs,” he told Vertical by email.

Loose Articles in a Crash Case

The securing of cargo seen on N690WA was also likely to be ineffective in a crash case. The H500 RFM only discusses internal cargo carriage with 1800 lb strength restraints attached tie tie down points.

In 2020 we published the case study: Alaskan AS350 CFIT With Unrestrained Cargo in Cabin

On 5 May 2016 AS350B2  N194EH of Era Helicopters, suffered a Controlled Flight Into Terrain (CFIT) while on approach northeast of Juneau, Alaska.  Cargo was loosely secured in the cabin.  As NTSB noted:

Review of the pilot’s post-accident medical treatment records indicated that his injuries included fractures of multiple left ribs and the left scapula, multiple left-sided transverse and spinous process fractures, as well as injuries to the left lung, left kidney, and spleen, and an intimal tear in the mid-descending aorta.

Contributing to the severity of the pilot’s injuries was the inadequately restrained internal cargo, which shifted forward during the impact and struck the pilot and/or the pilot’s seat.

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:


Aerossurance has extensive air safety, flight operations, SAR, HESLO, airworthiness, human factors, helidecks, aviation regulation and safety analysis experience.  For practical aviation advice you can trust, contact us at: enquiries@aerossurance.com