The crash site

Human error behind Wachey helicopter crash finds investigation report

In January 2023, The Bhutanese published an investigative story on the Royal Bhutan Helicopter Services (RBHSL) which pointed out the mistreatment of Bhutanese helicopter pilots by expat pilots, safety issues being overlooked, break down in relations between the pilots and more.

The Druk Air (which took over RBHSL) instead of acting on the news report grounded three of the Bhutanese pilots (in January 2023) who had written a complaint letter to the management saying the expat pilot and instructor Anton Sydney Hart was harassing and ill-treating the Bhutanese pilots.

Then on 3 March 2023 at 2.25 pm the Drukair A5-BHT Helicopter carrying a family of four passengers crashed at Wachey killing the mother and her daughter. The pilot was Stefan, from South Africa.

Cause, contributing factors and background

The Final Investigation Report on the crash essentially lays the blame down on human error and behaviour.

The investigation found nothing wrong with the engine and machinery of the helicopter.

The report says the probable cause was due to ‘Terrain impact due to the pilot attempting an abrupt change of its flight manoeuvre in a low approach which could have resulted in a loss of obstacle clearance.’

It said the contributing factors to the crash were failure to adhere to the pilot roster since another senior pilot was on active duty on the day of the accident, but the pilot involved in the accident operated the flights on that day. The pilot involved in the accident was on active duty for 6 consecutive days including the day of the accident.

The senior pilot who did not adhere to the roster was Anton Sydney Hart also from South Africa.

The report says the pilots failed to comply with the scheduled flight roster. The published flight roster for February and March 2023 indicates that another senior pilot (Anton) was designated for active duty on February 26, March 1, and March 3.

However, the pilot involved in the accident (Stefan) flew continuously from February 26, 2023, to March 3, 2023, covering 6 consecutive days before the accident.

The report says it indicates lack of proper communication and coordination among the pilots and also no proper supervision by the Head of Department. Additionally, there are indications of strained working relationship among the pilots.

The report said the pilot experienced emotional distress due to the bad attitude and reluctance of the senior pilot (Anton) to listen to him. The pilot involved in the accident was acting as an officiating supervisor while the supervisor was on leave.

The supervisor or the head pilot Abraham Karel Harmse also from South Africa was the one who hired Anton who was an old work colleague and Stefan.

In the article by The Bhutanese the first and former Chief Pilot of RBHSL Dave Peel from New Zealand had raised questions on Abraham’s mountain flying abilities.

Dave had said that the current head pilot Abraham, while being recruited, failed to clear two assessment tests done by him but two weeks later Abraham’s friend, also from South Africa, JB cleared him as an instructor. There is a copy of that report.

Abraham in the January article contested that he had not cleared the assessment by Dave, and said he was only assessed by JB.

According to sources Anton had been sulking and not flying his scheduled slots at the time leading to all the load coming on Stefan.

Under the contributing factors the investigation report says the pilot involved in the accident was not assertive enough to report the issues of the working environment to the supervisor and the management.

The report there was no proper supervision of the working relation among the pilots and the working environment by the supervisor and the management.

The January article by The Bhutanese had pointed to the lack of management support for the Bhutanese pilots and instead there was strong support for Abraham and Anton. As mentioned above the Bhutanese pilots were instead grounded by Druk Air for writing about Anton’s bad behaviour. The pilots were also not being given enough flying time by Abraham as this would mean the Bhutanese pilots would get more experience and be in a position to replace the highly paid expat pilots.

The paper had found three instances where Anton had behaved badly with security people as he was being arrogant while being checked in, and after the third instance he was given a final warning and a letter was sent to his CEO.

The paper had also talked to the Lunana Gup Kaka who confirmed that several people in Lunana had brought forward complaints to the Gup on the rude behaviour of Anton.

The investigation report as another contributing factor said there is also a history of the pilot performing aggressive manoeuvring at low approach.

The Bhutanese has found a video online where the same pilot Stefan can be seen making a similar manoeuvre that later led to the crash.

A former expat pilot said that the video showed unnecessary turns and stress on helicopter and basically there was no need for a big turn and there are also issues with the speed of approach. He said this is very unprofessional flying and he had sent the video to Abraham around six months before the crash.

This former expat pilot shared another longer video of a flight to Lunana where he says the chopper is low flying steep bank angles at high altitude with passengers on board. He said this is against the law for flying passengers and the former head captain Dave sent the video to the then RBHSL CEO but it was brushed under the table and the pilot involved was South African too.

He said that if pilots were caught doing that in Australia or New Zealand they would lose their jobs immediately.

“RBHSL (now Druk Air Helicopter) has developed a reckless culture which starts with the CEO (former RBHSL CEO),” he added.

Dave in The Bhutanese had said that in his time, he gave emergency trainings and tests every four months for everyone including the expats. He said that it is not enough that pilots know who to fly, but they should be able to respond to situations. 

Former expat pilot Alexandre Murta Collares (Alex) who was frustrated with Head Pilot Abraham and Pilot Anton for not giving enough flying hours to Bhutanese, had resigned in January 2023.

The investigation report says the Engine Data Recorder (EDR) analysis done by French Bureau d’Enquêtes et d’Analyses pour la sécurité de l’aviation civile (BEA) revealed no defects with the engine and all parameters were nominal during the entire flight until the suspected crash sequence.

Passenger account of reckless flying proved by machine recording

As per the pilot’s account, the helicopter was on its final approach towards landing site after making a successful turn, when it encountered sudden and violet change in wind direction, resulting in a loss of airspeed and lift. However, the survivor’s recollection differs, stating that the helicopter failed to recover from the sharp left turn and was still banking left when it lost lift, ultimately crashing among the trees.

A witness corroborated this by describing the helicopter’s left turn followed by a swift descent. The witness observed the helicopter banking left as it descended into the trees. According to the witnesses, the weather was fine with no clouds and no strong winds during the time of the accident. There were no adverse weather conditions like rain and snow but light winds are common at that time of the day (especially in the afternoon)

While the pilot and the passenger gave differing statements the helicopter equipment recording showed the passenger to be right.

The V2-Track trip profile indicates that the approach speed was about 65 knots and the rate of descend (ROD) during the approach was from 24 – 43 ft/min. The ROD is minimal which ties in with the low approach seen by the witnesses. During the approach, the heading change was from 359° at 08:23:39 (UTC) to 071° at 08:24:16 which was followed by sudden heading change from 071° to 332° within 15 seconds (99 degree heading change within 15 seconds).

This corroborates with the witness account of helicopter’s approach from Southwest to Northeast before making a steep left turn. The V2-track registered a climb during the left turn which seems to tie with the increase in collective.

Safety norms flouted

All the locals, witness and survivor stated that the approach and landing into Wachey has changed over the years. In the past, pilots used to make wider approach far from the landing site which was more comfortable to passengers as well. Moreover, wind curfew during windy season was strictly adhered in the past where no flights were operated after 2:30 P: M. A detailed pre-flight inspection by the pilot as well as maintenance engineer were carried out in the past. Recently, the approach paths are not consistent with what it used to be before and the wind curfew is also not adhered strictly.

The affected pilot has the track record of performing sharp manoeuvring at low approaches. On 1 March 2023, while landing at Khuruthang, the pilot’s aggressive manoeuvring was captured on video and corroborated by accounts from passengers on-board. These passengers, also serving as witnesses, reported a pattern of the pilot engaging in assertive and tightly controlled manoeuvres. Numerous witnesses and passengers have recounted their alarming experiences on several occasions with these flight manoeuvres.

It came apparent from the interview of ground staff and passengers that the passengers try to sneak in extra baggage without weighing it (hiding it from the ground staff). They try to load in the baggage that are not weighed and not accounted for.

There is also a norm where few extra luggage which comes above the weight limitations are accepted by the pilot/ground crew due to the commercial pressure and passenger requests.

However, in the flight crashed the luggage was within the norms.

The pilot was properly licensed and qualified to conduct the flight. He fulfilled the training requirements for direct entry pilots and also passed the medical and air law examination conducted by the BCAA. The pilot underwent a drug test on March 4 at JDWNRH and tested negative.

Safety recommendations

In its safety recommendations, the report says Drukair Helicopter Services shall encourage the pilots and crews to adhere to the roster and encourage the voluntary reporting of any safety issues concerning the organization and working environment.

Drukair Helicopter Services has been asked to strictly monitor the passenger and baggage weights prior to every departure and strictly adhere to the weight limit.

The Drukair Helicopter Services is to assess and comment on the overall flying style of the pilot during the 6 monthly Operators Proficiency Check (OPC) and take pre-emptive action in case of unconventional and unsafe manoeuvring by the pilots at any time.

Druk Air CEO responds

Responding to the investigation report the Druk Air CEO said they have gone through the observations and recommendations and they will give an officially reply. He said they had a meeting with the three post holders in the Helicopter Services and they will do an action taken report and reply to the Ministry. He said there will also do a lessons learnt and take preventive measures.

The CEO stressed that the report has mentioned pilot error as the ‘probable cause,’ only.

He said the pilot (Stefan) after recovery was let go as they cannot have a pilot who has committed an accident while in service.

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