Cattle mustering is a very dynamic operation that demands careful management, the ATSB warns. Image: Robinson
In the first of an occasional series, we take a look at recent accident reports and regulatory changes plus safety initiatives, analysing their impact.
Without question, the accident report that secured the most coverage both within and without the helicopter industry in the first three months of the year is the US NTSB’s final report into the January 2024 mid-air collision between a US Army Black Hawk and a CRJ700 airliner near Washington National Airport.
The report reveals much that has been long suspected by those who have operated in, out and around the airport.
Namely, that the airspace and in particular the low-level helicopter routes were of a design so poor that they beggared belief.
Furthermore, the failure by the FAA to react to the around 15,000 near-miss reports filed in the years leading up to accident borders on criminal negligence.
It would, however, be both unfair and inaccurate to lay all the blame at the FAA’s door, given that the US Department of Defense (DoD) had refused to consider changes to the way the airspace is used by military aircraft.
What makes this report different from the others we are reviewing in this edition is the high-profile nature of the accident, which prompted a flurry of activity by the FAA and others in its immediate aftermath.
The FAA introduced restrictions on heli-route use and created a new design of the airspace within a few weeks of the mid-air.
Meanwhile, in Congress, legislators busied themselves with the creation on Bills aimed at improving the safety of airspace in the US.
Indeed, even before the ink on the NTSB’s final report was dry, let alone issued, the first of these was the Rotorcraft Operations Transparency and Oversight Reform (ROTOR) Act, which gained Senate approval in December.
The ROTOR Act was subsequently voted down in the House of Representatives, prompting an angry response from NTSB Chairman, Jennifer Homendy, who posted on social media after the vote.
She wrote: “The Rotor Act would’ve saved lives; unlike claims that this is ‘emotional legislation,’ the FAA had over two decades to act and failed to do so. Had they acted, we wouldn’t be here today; families would have their loved ones. How many more people need to die before we act?”
Action and inaction
While Homendy gave the ROTOR Act her support and backing, she is less enthusiastic about the provisions contained in the ALERT Act, which is currently before the House.
She noted that the act “does not implement our most critical safety recommendations … it provides exemptions to lifesaving technology, technology that provides pilots and flight crews with information they need and deserve to ensure safety, technology that would’ve saved lives that night.”
But setting aside the political manoeuvrings of congressional politics, even if an amended ROTOR Act is passed or the ALERT Act moves forward – and it has made little progress; the latest update on the Congressional website shows it still in the committee stage – without adequate funding and resourcing of the FAA, the legislation will be nothing more than spiffy acronyms.
Gloucester, England – September 2019: Light aircraft taxiing after landing at Gloucester Staverton Airport. In the background a Bell Jetranger operated by Heli-Flight is landing.
Shortly after the accident, the FAA revealed that the design of the airspace at a number of other major airports had given it cause for concern, but due to lack of resources the agency made few if any changes outside the Washington area.
This changed earlier this year when restrictions on VFR operations were introduced around Los Angeles International Airport (LAX).
The FAA said: “As a result of the FAA’s proactive nationwide safety review of airports with mixed helicopter and airplane traffic, we are evaluating restricting Visual Flight Rules (VFR) operations near Los Angeles International Airport.
“While we conduct this evaluation, air traffic controllers will more often prohibit VFR operators from entering LAX airspace based on the volume and complexity of traffic they’re working, along with daily airspace occurrences including weather and any nearby construction.”
The initial application of the ruling had an immediate impact on police operations in certain parts of the city, with patrol officers on the ground being told they should not expect air support in those areas.
In mid-March, the FAA issued a general note (GENOT) amending the regulations for VFR aircraft in Class B and C airspace, as well as Terminal Radar Service Areas (TRSA), which ended the use of “see and avoid” VFR clearances to transit those types of airspace.
No bad thing, many would say. Mandatory radar service for zone transits is, after all, common practice in many parts of the world.
But what is interesting is that the GENOT change means that the requirement only applies to rotor-wing traffic. Which does seem to fly in the face of the logic of the regulation change – that “see and avoid” does not provide an adequate level of separation safety.
Also interesting is that Class D airspace around smaller airports is not included, despite many being extremely busy and populated with student and very low-time pilots.
Does it seem likely that once the furore about this accident abates there will be a slide back towards relative inactivity? It’s happened before, so it seems likely it will happen again.
Vuichard turns his attention to practice autorotations
A recent Transport Canada report into a fatal accident involving an AS350 on a training mission last May has prompted Claude Vuichard to argue that flight instructors and examiners should be aware that autorotations with power recovery present a risk of vortex ring state development.
In the case of the accident in question, a pilot was carrying out company training with a contract instructor/examiner in an area around five and half nautical miles east-southeast of Whitehorse/Erik Nielsen International Airport (CYXY), Yukon, in a valley with a dry lake bed immediately east of Grey Mountain.
Critically for the accident’s development once in the valley, there was little indication of wind direction.
After completing a number of aircraft handling and non-normal procedures exercises, the final sequence of tasks included a series of autorotations – including straight in and 180-degree autorotation exercises.
In the fifth and last autorotation flown by the pilot under instruction, the set-up was a straight in from the same direction as the previous evolutions.
When the helicopter was at approximately 100 feet AGL and travelling at an airspeed of 65 KIAS, a flare was initiated and the rate of descent (ROD) and airspeed decreased until the helicopter reached an airspeed of approximately 20 KIAS and a height of 70 feet AGL.
At this time, the ROD increased and the airspeed decreased further, to zero KIAS, with no reduction in ground speed.
Neither pilot was aware that the winds had shifted direction by about 180 degrees.
The training pilot identified that the helicopter had entered a fully developed vortex ring state (VRS) and took control of the helicopter. He attempted to exit the VRS by gaining forward airspeed. But at approximately 15:10 the helicopter impacted terrain before it had recovered from the VRS.
Vuichard’s take on the report is that it is “one that all pilots involved in training should read very carefully”.
He adds that an additional problem is that “the risk of a VRS is ever-present, even during a power recovery autorotations, which is what we mainly train for, and that the procedures published in flight manuals were actually designed only for power-off landings only.”
Vuichard recommends that in order to prevent a VRS during a power-recovery autorotation:
- Avoid any tailwind component
- Avoid excessive flares
- The most effective method is to begin the flare with a rotor preload of approximately half an inch, then initiate the flare with the cyclic. This technique immediately brings the rate of descent outside the VRS build-up sector, thereby eliminating VRS during the power-recovery autorotation. Due to the preload, a much smaller flare is required, only about 15 degrees nose up, which in turn requires much less rotor energy for touchdown.
Vuichard points out that civil aviation authorities, such as the European Aviation Safety Agency (EASA) and the Federal Aviation Administration (FAA), should require original equipment manufacturers (OEMs) to provide descriptions of autorotations with power recovery. This would help to prevent accidents caused by vortex during training.
Mustering mid-air has familiar ring
The Australian Transport Safety Board (ATSB) has released its final report into the June 2024 fatal mid-air collision between two Robinson R22 Betas engaged in cattle mustering operations.
Vuichard says the most effective method is to begin the flare with a rotor preload of approximately half an inch, then initiate the flare. Image: Claud Vuichard
The report says that between first light and sunrise on the morning of the accident the pilots of four Robinson R22s planned to take-off from the Mount Anderson Station homestead in Western Australia’s Kimberley to transit to a mustering site about a 10-minute flight away.
Shortly after take-off, two of the helicopters collided about 150 ft above ground level. As a result, both helicopters departed controlled flight and collided with terrain.
The ATSB investigation established that the helicopters collided during their initial climb, after the lead helicopter had manoeuvred to the right.
In a finding eerily similar to that of the Gold Coast mid-air between two sightseeing H130s, the investigation found that the two pilots were unaware of the threat until the point of collision.
Chief Commissioner, Angus Mitchell, said: “Neither pilot detected their converging flight paths before the collision. While limited data prevented a full visibility study to establish what each pilot could see, the wreckage examination indicated that at the point of collision the lead helicopter may have been in a blind spot for the second helicopter.”
Vuichard argues that regulators should require OEMs to provide descriptions of autorotations with power recovery. Image: Claude Vuichard
The investigation report considers what actions the helicopters’ operator, Pearl Coast Helicopters, was taking to manage aircraft separation in its operations.
Mitchell said: “The tools used by the operator to consider and manage operational risk were not tailored to their main business of aerial mustering. Further, the risk of collision had not been identified in operational risk assessments, and the operator’s manuals did not provide documented procedures to ensure pilots establish and maintain adequate separation between helicopters.”
Instead, the final report notes, company pilots were permitted to arrange their own separation based on personal preference.
“Pilots routinely flew with reduced vertical and lateral separation, and over time this became an accepted operating preference.”
Angus Mitchell, Chief Commissioner, ATSB
Mitchell said the accident was a demonstration of the need for risk management to identify, assess and mitigate risks.
“Aerial mustering plays a critical role in Australia’s agricultural sector. This tragic accident should serve as a trigger for all mustering operators to consider their risk-management practices and whether they have scaled them adequately for their operation.”
Mitchell added that the accident was another reminder of the fallibility of see-and-avoid as a primary means of identifying and managing the threat of collision.
He said: “Defined separation minimums and pre-planned safe exits which provide an opportunity to identify and respond to emerging collision threats are important tools in assisting pilots avoid mid-air collisions.
“Additionally, airframe obstructions can limit visibility in even the most open cabins. This should be a key consideration when establishing how aircraft should be positioned when flying in close proximity.”
This article “Causes and effects” was published in the Volume 20 Issue 1 of RotorHub International. To read more articles like this, apply for your complimentary subscription today.
