Preliminary report released for fatal helicopter accident near Coalinga

The UH-1H crashed August 19, 2020

Flight path of UH-1H from the NTSB preliminary report
Flight path and pilot statements from the NTSB preliminary report.

The National Transportation Safety Board has released a preliminary report on the August 19, 2020 helicopter crash in which pilot Mike Fournier, 52, was killed. He was the only person on board.

The Bell UH-1H helicopter, N711GH, crashed while on a water dropping mission on the Hills Fire, approximately 9 miles south of the City of Coalinga. It was operated by Guardian Helicopters out of Van Nuys, California on a CAL FIRE contract.

The early evidence from the NTSB indicates there was a problem with the hydraulics, based on radio communications from the pilot moments before the accident.

The Associated Press reported that Mr. Fournier’s wife and two daughters filed suit against the helicopter’s manufacturer and the company that serviced it. Both were accused of negligence and wrongful death in the suit that seeks unspecified damages.

Below is the complete text from the narrative section of the NTSB preliminary report (Accident #WPR20LA280). It will be months before the agency completes and releases the final report which may come to a conclusion about the cause of the accident.


“On August 19, 2020 about 0945 Pacific daylight time, an Arrow-Falcon Exporters, Inc. UH-1H, N711GH, was destroyed when it was involved in an accident near Coalinga, California. The pilot, the sole occupant was fatally injured. The helicopter was operated as a public use firefighting flight.

“The accident flight was the pilot’s first day working the Hills Fire, which had started four days prior. The pilot departed at 0846 followed by another pilot that was flying a Bell 212 helicopter for another operator.

“Investigators reviewed flight track data covering the area of the accident during the time surrounding the accident. Additionally, the Bell 212 pilot had an app recording his track that he provided to investigators. After departure, both helicopters flew south until reaching a small lake/reservoir (the dip site) to fill up the external load buckets attached to their respective helicopters (bambi buckets). Thereafter, they flew to a predetermined areas and began to unload their water on the fire. After releasing the water, they would return back to the dip site. After the accident pilot delivered about two buckets of water to a division he moved to another division delivering about five buckets of water.

“The Bell 212 pilot recalled that after he departed the dip site with a bucket of water, he heard the accident pilot communicate over the air-to-air radio that he felt “abnormal noises and vibrations” and that he was going to make a precautionary landing. The Bell 212 pilot dumped his water and then caught up to the accident helicopter with the intention of assisting the pilot find a good area to land; he remained a few hundred feet behind and above the accident helicopter. The accident helicopter was about a 1,000 ft above ground level (agl) and maneuvering at an airspeed between 60 to 70 kts. The accident pilot then stated that the helicopter’s “temps and pressures are good.” A few seconds later the accident pilot stated “it’s my hydraulics.” (See Picture 1 below). The Bell 212 pilot relayed that that he should make a right turn and fly down the ravine to less mountainous terrain (the flats).

“The helicopter started to make a right turn and then banked back to the left while losing airspeed. The Bell 212 pilot noticed the helicopter still had its 100 ft longline and bambi bucket attached and told the accident pilot to “release your long line and get forward airspeed,” The accident pilot then stated “Mayday, Mayday, Mayday.” The left turn steepened remaining in a level pitch attitude, and the helicopter began to make three or four 360° rotations (rapidly swapping the front and back), while drifting north-east. The helicopter then pitched in a nose-low, near vertical attitude and collided into terrain. (See Picture 2 below). A fire immediately erupted and the Bell 212 pilot made multiple trips to the dip site to fill his bucket and drop water on the accident site.

“The helicopter came to rest on a 35° slope with the main wreckage about 25 yards downslope from the initial impact. A majority of the wreckage was consumed by fire; the tail rotor assembly was intact. The tail rotor blades were intact, with no evidence of rotational scoring. The wreckage was recovered to a secure location for further investigation.”

(end of NTSB report)


N711GH Guardian Helicopters
File photo of N711GH. Guardian Helicopters photo.

During a 49-day period that began July 7, 2020 there were six crashes of firefighting aircraft — three helicopters and three air tankers. In addition, three members of the crew of a C-130 from the U.S. died when their air tanker crashed January 23, 2020 while fighting a bushfire in New South Wales, Australia.

Thanks and a tip of the hat go out to Tom.

Reports released about the helicopter that crashed on the Polles Fire in Arizona

The pilot was killed in the July 7, 2020 accident west of Payson

Polles Fire vicinity map
Polles Fire vicinity map

On July 7, 2020 a UH-1H helicopter crashed while transporting supplies to firefighters who were spiked out (camping) while working on the Polles Fire about 10 miles west of Payson, Arizona. The only person on board, pilot Bryan Jeffery “BJ” Boatman, 37 of Litchfield Park, Arizona was killed. We send our sincere condolences to the family and friends of Mr. Boatman, and to the forestry technicians who were at the fire.

Bryan Jeffery “BJ” Boatman
Bryan Jeffery “BJ” Boatman

BJ was born on June 8, 1983 in Provo, Utah. He was a third-generation pilot and worked alongside his parents to build their company, Airwest Helicopters of Glendale, Arizona.

3-D map of the Polles Fire from data at 10:36 p.m. July 7, 2020
3-D map of the Polles Fire from data at 10:36 p.m. July 7, 2020; looking north.

The helicopter, N623PB, serial number 64-13689, was manufactured in 1964. It is a UH-1H registered to Aero Leasing in Glendale, Arizona, the same city where Air West Helicopters is located.

Polles Fire - Payson helicopter crash fatality
Airwest Helicopters photo, N623PB.

Two reports have been released, a brief preliminary report by the National Transportation Safety Board, and a 23-page facilitated learning analysis (FLA) commissioned by the U.S. Forest Service.

The FLA is solely devoted to analyzing the response to the accident — the Incident Within an Incident and the actions taken in the following days. It does not address what caused the helicopter to crash. The report found very little to criticize and praised most of the actions that were taken. It goes into quite a bit of detail about how the fire’s Incident Management Team handled the emergency response during the first few hours, as well as organizing over the next several days to care for BJ’s family and the forestry technicians that were involved.

Anyone who could in the future find themselves in a similar unfortunate situation would benefit from reading the FLA. Firefighting is dangerous, and others will have to walk the same path.

During a 49-day period that began July 7, 2020 there were six crashes of firefighting aircraft — three helicopters and three air tankers. In addition, three members of the crew of a C-130 from the U.S. died when their air tanker crashed January 23, 2020 while fighting a bushfire in New South Wales, Australia.

Below is the text from the narrative portion of the three-page NTSB report. The complete report which will analyze the cause, might be released within the next year.


“On July 7, 2020, about 1213 mountain standard time, a Bell/Garlick UH-1H helicopter, N623PB, was destroyed when it was involved in an accident near Payson, Arizona. The pilot was fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 133 external load flight.

Illustration from the NTSB report
Figure 1: Depiction of helicopter flight path based on witness statements. From the NTSB preliminary report.

“The helicopter was owned by Airwest Helicopters LLC and operated by the United States Forest Service at the time of the accident. According to witnesses, the helicopter was transporting supplies using a long line for a hotshot firefighting crew that were repositioning on the ground. The pilot transported three loads to the new destination uneventfully prior to the accident and had been using an indirect route to the north to avoid a fire area (Figure 1). While transporting the fourth load, witnesses observed the helicopter begin to fly erratically while en route to its destination. During this time, a witness stated that he observed the helicopter enter a high nose-up pitch attitude and the external payload began to swing. The helicopter then displayed irregular movements for several seconds before the external payload settled and the helicopter appeared to stabilize. However, after about 3 seconds, multiple witnesses observed the helicopter wobble and bank erratically before it entered a steep nose up attitude and then descended rapidly. The witnesses did not observe the helicopter on fire during the accident flight, nor did the pilot report any anomalies over the helicopter crew’s common air-to-ground radio frequency or any other assigned frequencies for the fire.

“The helicopter wreckage came to rest about 0.5 nm north of its drop off destination, oriented on a heading of 074° magnetic and was mostly consumed by postcrash fire. All major structural components of the helicopter were accounted for at the accident site. The helicopter’s external payload was found 123 ft southeast of the main wreckage.

“The wreckage was retained for further examination.”

Royal Commission recommends aerial firefighting fleet for Australia

helicopter drops water Australia
A helicopter drops water during the 2019-2020 bushfire season in Victoria, Australia.

The unprecedented 2019-2020 bushfire season in Australia resulted in the devastating loss of life, property, and wildlife across the nation. After the smoke cleared a Royal Commission was directed to work out not only how to prevent the severity of future bushfire seasons, but all natural disasters.

Wildfire Today has a lengthy article covering many of the issues identified in the Commission’s 594-page report, but below are excerpts from the section about aerial firefighting.


Capabilities of national aerial firefighting

  • The Victorian Inspector-General for Emergency Management observed that, “The effectiveness of aerial firefighting resources and the deployment system in Victorian environments has not been extensively evaluated. A greater understanding of how aerial assets can support suppression efforts including first attack would allow Victoria to make more informed requests for aerial firefighting assets and ensure any assets provided are used to their greatest effect.” The governments of ACT, SA and Victoria also told us that they consider further research is required to improve aerial firefighting tactics, products and their effectiveness.
  • Aerial firefighting capabilities vary between the states and territories, with some jurisdictions, such as the ACT, not owning any aircraft. Other jurisdictions own aircraft. For example, NSW owns a fleet consisting of three helicopters and the ‘Marie Bashir’ LAT, and has purchased a further four aircraft (two fixed-wing and two helicopters) which are expected to be available in 2020. [Note from Bill: The LAT is a 737 air tanker recently purchased from Coulson Aviation. The two fixed wing aircraft are Cessna Citation Lead/Intelligence jets; the two helicopters are Bell 412s. More info.]
  • There is merit in considering what further benefits could be derived from even greater [interstate] collaboration in the use of available aerial firefighting resources.
  • We heard that the current terms of aircraft service contracts are a disincentive for some Australian-based service providers. The majority of the providers we heard from told us that short contracts and minimal work during the off season make it unviable to invest in expensive aviation equipment. Contracts traditionally engage providers for 84 service days (70 in Tasmania) within the fire season, but we heard that more contracted service days would allow providers to invest in more equipment and offer greater value for money to fire agencies.
  • The Aerial Application Association of Australia also told us that the length of contracts is insufficient to encourage industry to invest in aircraft and creates significant uncertainty in securing long-term finance. The Aerial Application Association of Australia also criticizes the short lead times for developing contract proposals with NAFC.
  • The limited availability of aviation support personnel in Australia during the 2019-2020 bushfire season limited the sharing of personnel between jurisdictions and led to a greater reliance on personnel sourced from overseas.
  • The optimal use of aerial firefighting is in the early stages of a bushfire. For an aircraft to provide effective assistance in the suppression of a bushfire it needs to be rapidly dispatched with minimal travel time and with necessary logistical support systems in place. Victoria, SA and WA each employ ‘pre-determined dispatch’-the purpose of which is to reduce the time for the aircraft to reach the fire -described as a ‘game changing system that should be adopted nationally’.
  • On some occasions during the 2019-2020 bushfire season states and territories were unable to call upon additional aviation services when needed.
  • Aviation services funded, in whole or in part, by the Australian Government should be shared between jurisdictions according to the greatest need.
  • The availability of overseas-based aviation services during Australian fire seasons, particularly LATs, may be reduced by the increasing convergence of fire seasons in the northern and southern hemispheres.
  • We also heard that Australian-licensed pilots were not licensed to operate foreign-registered aircraft used in Australia during the 2019-2020 bushfire season. For example, with the exception of the NSW-owned LAT, none of the LATs used in Australia during the 2019-2020 bushfire season were Australian-registered, and therefore Australian-licensed pilots were precluded from operating them.
  • The Australian Federation of Air Pilots told us that it has approximately 5,000 Australia-based members employed as commercial pilots. This suggests Australia may have the potential to recruit and train the necessary expertise to operate firefighting aircraft currently sourced from overseas, including LATs, if such aircraft were owned and registered in Australia.
  • Australian, state, and territory governments should work together to continue to improve Australia’s collective, Australian-based and operated, aerial firefighting capabilities. Though we see merit in the continued use of overseas-based aviation services and air crew in some instances, Australia’s current reliance represents a vulnerability, as demonstrated during the 2019-2020 bushfire season.
  • The development of a modest Australian-based and registered national fleet of VLAT/LAT [Very large Airtanker/Large Air Tanker] aircraft and Type-1 helicopters, jointly funded by the Australian, state and territory governments, will enhance Australia’s bushfire resilience. A standing national fleet would ensure that the states and territories have the necessary resources to call upon during periods of high demand, without the need to reduce the operational capabilities of other jurisdictions. This standing fleet should also include situational awareness and support capabilities which may benefit from a nationally coordinated approach. Australia’s sovereign aerial firefighting capability should be supported by ongoing research and evaluation to inform specific capability needs, and the most effective aerial firefighting strategies.
  • Australia’s sovereign aerial firefighting capability may be supplemented by overseas-based aviation services, where additional capacity is forecast to be required and available.

Preliminary report released for fatal SEAT crash in Idaho

The pilot was killed September 22, 2020 southeast of Emmett, Idaho

October 16, 2020   |   3:56 p.m. MDT

NTSB preliminary report T-857
Image from the NTSB preliminary report on the September 22, 2020 crash of a SEAT in Idaho.

The National Transportation Safety Board has released a preliminary report on the fatal crash of a single engine air tanker (SEAT) in Idaho.

The Air Tractor AT-802A crashed September 22, 2020 while working on the Schill Fire, approximately 2 miles southeast of Emmett.

The pilot, Ricky Fulton, perished. The aircraft, Tanker 857, was owned by Aero S.E.A.T. Incorporated and was on an on-call (CWN) contract with the Bureau of Land Management. The aircraft was first registered July 10, 2020, FAA registration number N836MM.

Typically it takes 8 to 16 months for the NTSB to issue their final, complete report with an analysis of the causes of a crash.

This was the sixth firefighting pilot and the third SEAT pilot to be killed in the United States this year. In addition, three members of the crew of a C-130 from the U.S. died when their air tanker crashed January 23, 2020 while fighting a bushfire in New South Wales, Australia. Also, one person was killed August 8 in the crash of a CL-215  based in Portugal while battling a fire in Spain.

Below is the complete text from the narrative section of the report about the September 22 crash.


On September 22, 2020, about 1830 mountain daylight time, an Air Tractor AT-802A, N836MM, was substantially damaged when it was involved in an accident near Emmett, Idaho. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 aerial firefighting flight.

Witness conducting firefighting operations, adjacent the accident site, reported that the accident airplane, a single engine air tanker (SEAT), descended and made an approach similar to the previous SEATs that were dropping fire retardant. The witnesses said the airplane passed over the top of the ridge and descended into the valley, however, the pilot did not drop the fire retardant as previous SEATs did. The witnesses stated he heard a brief application of engine power as the airplane began to ascend over rising terrain at the pilot’s 12’oclock position. The airplane subsequently impacted rising terrain near the peak of the ridgeline.

A video provided by a witness captured the accident sequence. The recording showed the airplane descend over an intermediate ridgeline and into a valley (see figure 1). About 3 seconds later, the airplane momentarily returned to level flight before it pitched to a nose-high attitude. The airplane subsequently impacted rising terrain approximately 80 feet below the ridgeline.

Examination of the accident site by a Federal Aviation Administration inspector revealed that the airplane impacted rising terrain. The wreckage debris path continued from the initial impact point over the top of a ridgeline, and extended into a small ravine. The airplane came to rest approximately 100 yards from the initial impact pointe on a heading of 040 degrees. All major structural components of the airplane were located throughout the wreckage debris path. The wreckage was recovered for further examination.

(end of report)


Thanks and a tip of the hat go out to Matt.

Interim report released for fatal air tanker crash in Australia

All three crewmembers were killed in New South Wales, January 23, 2020

Flight path B134 air tanker crash

The Australian Transport Safety Bureau (ATSB) has released an interim report about the January 23, 2020 crash of a C-130, Air Tanker 134, that killed the three crewmembers on board. This follows the preliminary report the agency issued in February, 2020. The aircraft was known as Bomber 134 (B134) in Australia.

“The interim report does not contain findings nor identify safety issues, which will be contained in the final report. However, it does detail the extensive evidence gathered to date, which has helped ATSB investigators develop a detailed picture of this tragic accident’s sequence of events,” said ATSB Chief Commissioner Greg Hood.

Tanker 134 at Medford, Oregon
Tanker 134 (B134) at Medford, Oregon July 27, 2019. Photo by Tim Crippin.

It was very windy on January 23, with a forecast for the possibility of mountain waves. Before the incident a birddog, similar to a lead plane, and  Bomber 137 (B137), formerly Tanker 138, a Boeing 737 that Coulson sold to New South Wales, was tasked to drop on a fire in the Adaminaby area. Based on the weather the birddog pilot declined the assignment. After B137 made a drop on the fire, the crew reported having experienced uncommanded aircraft rolls up to 45° angle of bank (due to wind) and a windshear warning from the aircraft on‑board systems.

After completing the drop, the B137 crew sent a text message to the birddog pilot indicating that the conditions were “horrible down there. Don’t send anybody and we’re not going back.” They also reported to the Cooma FCC that the conditions were unsuitable for firebombing operations. During B137’s return flight to Richmond, the Richmond air base manager requested that they reload the aircraft in Canberra and return to Adaminaby. The Pilot in Command (PIC) replied that they would not be returning to Adaminaby due to the weather conditions.

B134 was dispatched to the fire at Adaminaby. While they were in route, the PIC of B137 called to inform them of the actual conditions, and that B137 would not be returning to Adaminaby.

After arriving at Adaminaby the PIC of B134 contacted the air operations officer at the Cooma FCC by radio and advised them that it was too smoky and windy to complete a retardant drop at that location. The Cooma air operations officer then provided the crew with the location of the Good Good Fire, about 58 km to the east of Adaminaby, with the objective of conducting structure and property protection near Peak View. Again, there was no birddog operating with the air tanker.

B134 flight path air tanker crash
Flight path overview (in white), including the times and locations of where the crew of B134 was in communication with others. From the report.

Analysis of a witness video confirmed that the aircraft initially established a positive rate of climb and was banking to the left following the retardant drop, the report details. Continue reading “Interim report released for fatal air tanker crash in Australia”

Preliminary report reveals one of the SEATs involved in the July 30 mid-air collision had retardant on windshield

Two pilots were killed July 30, 2020 at the Bishop Fire in southeast Nevada

NTSB graphic mid-air crash air tanker
NTSB graphic of the last flights of N1558W (Tanker 824) and N8510M (Tanker 866).

A preliminary report released by the National Transportation Safety Board revealed that one of the two Single Engine Air Tankers (SEAT) that collided and crashed July 30, 2020 had fire retardant on the windshield. Both pilots of the aircraft, the only personnel on board, were killed while assisting firefighters on the Bishop Fire in southeast Nevada.

The investigators found that the tankers were working in tandem with one close behind the other. After the following aircraft got retardant on the windshield it made a rapid climb then suddenly turned left and collided with the other.

Both of the SEATs were operated by M&M Air Services out of Beaumont, Texas but the names of the two pilots have not been released. The aircraft were made by Air Tractor, model AT-802A; N8510M (Tanker 866) and N1558W (Tanker 824).

Below is the complete text of the preliminary NTSB report:


On July 30, 2020, about 1256 Pacific daylight time, two Air Tractor AT-802A airplanes, N8510M and N1558W, were destroyed when they were involved in an accident near Elgin, Nevada. The pilots of both airplanes were fatally injured. The airplanes were operated as public use firefighting flights.

The airplanes were functioning as single-engine airtankers (SEATs) for the Bureau of Land Management providing aerial firefighting services at the time of the accident. According to automatic dependent surveillance broadcast data (ADS-B) and witness statements, the airplanes departed Mesquite, Nevada as a flight of two about 1225 to deploy their third load of fire retardant that day. ADS-B data showed that N8510M was in lead and N1558W was in trail as they flew northeast towards a designated fire traffic area in a climb. At 1252:47, the pilot of N8510M started a descent from 7,100 ft msl accompanied by a slight right turn to the north and then he turned west about 15 seconds later. N1558W followed the movements of N8510M from about 1,500 ft behind him. About this time a lead airplane had begun to escort the flight of two SEATs to their intended drop area. At 1254:37, N8510M turned left to a southeast heading and descended from about 6,000 ft msl, with N1558W still about 1,500 ft in trail. N1558W began a turn to the southeast a few seconds later and descended from 6,100 ft msl, but when they leveled out, N1558W was about 500 ft in trail of and 100 ft below N8510M. The data showed that the airplanes were in a descent about 400 ft above ground level when the ADS-B data ceased temporarily at 1955:23 for N8510M and at 1955:28 for N1558W. The data for N8510M resumed at 1255:38 and showed the airplane in a climb along a southeast heading. The track for N1558W resumed at 1255:45 and showed the airplane in a climb on a similar heading about 70 ft in trail and 125 ft below N8510M.

Video recorded by a ground witness captured both airplanes seconds before their collision, which showed N8510M descend to a low altitude, deploy fire retardant, and then immediately begin a shallow climb. The video showed N1558W following very close in trail of N8510M during this time. N1558W then deployed fire retardant and began a rapid climb. Witnesses in nearby firefighting aircraft stated that they heard the pilot of N1558W announce over the radio that he had retardant on his windshield and was initiating a go-around. According to witnesses on the ground, as N1558W climbed, it suddenly began a left turn and collided with N8510M. Both airplanes then descended rapidly to the ground.

Postaccident examination of the accident site revealed that N8510M was mostly consumed by a postimpact fire. The wings and forward fuselage of N1558W came to rest about 315 ft beyond N8510M and did not burn. The tail section of N1558W, was located about 450 ft northwest of the forward fuselage and was partially damaged by postimpact fire.

The wreckages were retained for further examination.


Red Canyon Fire
File photo of air tanker 866 (N8510M) dropping on the Red Canyon Fire in South Dakota July 9, 2016. Photo by Bill Gabbert.
Tanker 824 (N1558W)
File photo of tanker 824 (N1558W) at Boise, July 19, 2014. Photo by Bill Gabbert.

Thanks and a tip of the hat go out to Dale.

Preliminary information released about fatal helicopter crash in Arizona

Bryan Jeffrey Boatman
Bryan J. Boatman

The U.S. Forest Service has released preliminary information about the helicopter crash in which pilot Bryan Jeffrey Boatman, 37, was killed.

It occurred on the Polles Fire in central Arizona when Mr. Boatman was approaching a helispot delivering supplies by long line to firefighters in a remote area.

He was the only person on board the aircraft.

Below is the narrative from the Forest Service’s Preliminary Brief:

Narrative: On Tuesday, July 7, 2020 at approximately 1216 MST, a UH-1H helicopter, N623PB, impacted terrain with one occupant on board. The aircraft was performing long-line cargo delivery operations in support of fire suppression on the Tonto National Forest when the mishap occurred. The aircraft was under exclusive use contract with the USFS.

The NTSB investigation into this accident is ongoing. At this time, there are no indications of immediate safety concerns with other similar make/model of aircraft. All matters related to public information must be disseminated through the NTSB.

Mr. Boatman flew for Airwest Helicopters out of Glendale, Arizona. He leaves behind his wife Elizabeth Marie Boatman and his 8-year old daughter Claire Elizabeth Boatman. The family chose to hold a private funeral service. Donations in his memory may be made to the Wildland Firefighter Foundation (wffoundation.org).

UH-1H N623PB
UH-1H N623PB. Training in 2016. Photo: Jose Navarro.

Report released for crash of Air-Crane helicopter into lake

The accident occurred in Australia in January, 2019

Air-crane helicopter crash Australia report
From the ATSB report.

The Australian Transport Safety Bureau determined that the Air-Crane helicopter that crashed into a lake January 28, 2019 in Victoria, Australia was a victim of vortex ring state (VRS). The accident occurred on a firefighting mission as it descended to draft water at a narrow lake with steep sides.

From the report released April 17, 2020:

The topography, high rate of powered descent, and steep flare that reduced the airspeed, created conditions conducive to the onset of VRS. The crew reported that the rapidity of onset and dimensions of the dip site did not provide enough time or space to maneuver sideways to effect a recovery.

Air-Crane crash Australia helicopter
The Air-Crane crashed in a lake surrounded by rising terrain.

Here is what I wrote about the accident on January 28, 2019 in a comment below the report of the accident:

If the helicopter was attempting to hover to draft water to refill its tanks, the fairly narrow section of the lake with what appears to be steep rising terrain nearby may have been a factor in the confined space. The Air-Crane has six blades on the main rotor with a diameter of 72 feet. It may have encountered what helicopter pilots refer to as a “Vortex Ring State” or VRS. The canyon slopes may have prevented the massive rotor wash from diffusing and could have caused the cushion of air beneath it to become chaotic as the helicopter neared the water surface, reducing lift.

VRS in addition to density altitude was a factor in the crash of the MH-X Silent Hawk that transported Seal Team 6 as they attacked the hideout of Osama bin Laden in Pakistan in 2011. The helicopter was landing inside a yard surrounded by high walls when it lost lift. The pilots had practiced landing in a full-scale model of the site, but the walls in the model were represented by chain link fencing material, and were not solid like the walls around Osama bin Laden’s house. The rotor wash would have been more easily diffused through the chain link fence during the rehearsals.

Air-Crane 341
Air-Crane 341. From the report.

Two crewmembers were not injured, but one sustained a knee injury. In May, 2019 the helicopter was recovered after a complex salvage process.

Air-Crane extracted from lake crash

Below are excerpts from the ATSB report about the Air-Crane incident (which you can view here):


…After a number of water drops, the aerial attack supervisor (AAS) re-tasked the crew to fight a flame front further north, which was east-northeast from the dip site. Each drop was also incrementally further north. This resulted in the crew gradually tightening the approach to the dip site.

During the occurrence approach, the tighter approach resulted in a greater than normal flare to arrest the aircraft at the aiming point in the dip site. The higher nose pitch up prompted the SIC to advise the PIC to move forward of the trees before descending any further to ensure tail rotor clearance. Clear of the trees, the flare was increased.

While descending with a nose-high attitude, the aircraft struck the water tail-first, submerging and removing the tail rotor, causing rapid rotation to the right through one and half turns. While rotating, the main rotor blades separated as they contacted water. The right cockpit door separated from the fuselage, and the aircraft came to rest on its left side, submerging the cockpit.

Each crewmember recalled the rehearsed drills from their helicopter underwater escape training (HUET). They identified their seat belt and nearest exit to orientate themselves in the aircraft. They all waited until the last moment to draw a breath, and did not unbuckle and exit the helicopter until motion had ceased. The crew reported that it was not possible to see anything underwater, and that jet fuel contamination was present.

The SIC in the right seat exited through his doorway, from which the door was already missing. The PIC could not open his door so he swam across the cabin (up) and was assisted by the SIC to exit through the right hand door. As the rear door was jammed, the crew chief in the aft seat pushed out a window from the rear of the cabin, and exited through it.

Neither pilot unplugged their helmet. However, the extension cords from the aircraft to the helmet plug allowed the plug to release, preventing the helmets from snaring the pilots. All three crew escaped, and inflated their life jackets. Two crew were uninjured, and one crewmember sustained a knee injury.

At the time of the accident, crews aboard S-76 and S-61N helicopters were assessing the potential of the dip site for later use in night operations. An AAS aboard the S-76 relayed details of the accident to an incident controller who enacted the emergency response plan. Neither the S-76 nor the S-61N was equipped or able to provide direct assistance, other than monitoring, and relaying information. Following exit from the helicopter, the only form of communication available to the Skycrane crew was hand signals. They gave thumbs-up indications to the crew of the overhead S-61N to advise that they were okay. The Skycrane crew then swam to shore and trekked through dense bush to a road where they were met by rescuers.

Findings
These findings should not be read as apportioning blame or liability to any particular organization or individual.

  • The crew conducted a tight descending right hand turn into the dam [lake], inside the upper margins of the flight envelope. This approach required a steep flare on arrival and likely resulted in the rapid onset of vortex ring state.
  • The dam’s [lake’s] steep sides and narrow tapered body provided limited opportunity for vortex ring state recovery actions, contributing to collision with water.
  • The Crew Chief’s presence aboard the aircraft during firebombing operations exposed him to unnecessary risk.
  • All crewmembers credited their survival to skills learned and practiced in Helicopter Underwater Escape Training. In addition, the helmet cord extension cables detached easily from the aircraft, contributing directly to the crew’s egress from the flooded cockpit.