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Helicopter/Cyclone discussion (split from HMCS Fredricton thread)

Lance Wiebe

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SeaKingTacco said:
No. It was not a software “bias”. A bias signal built up in pitch channel in Flight Director mode of the Flight Control Computer. It is important to get the terms correct. And since the flight safety investigation is only at an early stage, I am certain a lot more factors will come to light in the coming months. Remember- accidents are complex events consisting of many discrete events that contribute.

I must admit, when the article mentioned it was a software bias, and not a software coding error, I was confused.
I have never heard of a software bias before I read the article.

I am happy to be corrected.
 

Ping Monkey

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Out of curiosity, does anybody know how similar the CH-148 and VH-92 (https://en.wikipedia.org/wiki/Sikorsky_VH-92) flight control systems are?  I presume they'd be close/identical.  (I also realize the mission suites are completely dissimilar.)


I was at NAS Patuxent River in March and was pleased to see one conducting flight testing at the time.  From a distance, I thought a Cyclone was on its way into the circuit.


Given the "high profile tasks" that the VH-92 will perform, I'd believe if this if this problem is common in both airframe types, Sikorsky would be getting some pressure by the testing community in Pax River to ensure any flight control issues discovered from this accident and during CH-148 testing are resolved for their fleet.
 

Colin Parkinson

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Baz said:
And everything I just wrote seems like a "haze of technical jargon."  Does the public really need to understand all that?

Since the public is paying for it and providing the recruits to fly them in the future, then I would say yes. You can have the technical description with a brief summary. It's best to get one of your own to write the summary in layman's language, otherwise the media will get it wrong. They may still butcher for their own reasons, but anyone with further interest can then read the press release.
 

Eye In The Sky

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The problem, then, is reporters who admittedly know nothing about the subj then putting things into words they think people will understand that only ends up misleading them;  things like the words "software glitch".
 

observor 69

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"Around the world, fly-by-wire helicopters are rare — as are the experts who understand them"

Murray Brewster · CBC News · Posted: Jun 18, 2020 4:00 AM ET | Last Updated: 1 hour ago"

A well-written article by Mr. Brewster with perhaps some new info for us non-rotary wing types.

https://www.cbc.ca/news/politics/cyclone-chopper-helicopter-crash-fly-by-wire-1.5616809






 

dapaterson

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Baden Guy said:
"Around the world, fly-by-wire helicopters are rare — as are the experts who understand them"

Murray Brewster · CBC News · Posted: Jun 18, 2020 4:00 AM ET | Last Updated: 1 hour ago"

A well-written article by Mr. Brewster with perhaps some new info for us non-rotary wing types.

https://www.cbc.ca/news/politics/cyclone-chopper-helicopter-crash-fly-by-wire-1.5616809

Expert cited: https://www.jurispro.com/expert/shawn-coyle-5640  He has 6500+ hours rotary wing flight; CAF pilot 1969-1984; test pilot; worked with Transport Canada as well.
 

SeaKingTacco

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Baden Guy said:
"Around the world, fly-by-wire helicopters are rare — as are the experts who understand them"

Murray Brewster · CBC News · Posted: Jun 18, 2020 4:00 AM ET | Last Updated: 1 hour ago"

A well-written article by Mr. Brewster with perhaps some new info for us non-rotary wing types.

https://www.cbc.ca/news/politics/cyclone-chopper-helicopter-crash-fly-by-wire-1.5616809

No, not well written. He has stated things in the article that are the precise opposite of what was said at the technical briefing. He has badly mis-stated how bias works and and how temporary deviations from a programmed flight path while in Flight Director mode work (in fact, temporary deviations have no real impact). He implies the pilots were flying via some sort of keyboard which is just ridiculous, when you think about it. He compares this accident to the 737Max accidents, when DFS specifically stated that he did not see a linkage.

 

Good2Golf

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Baden Guy said:
"Around the world, fly-by-wire helicopters are rare — as are the experts who understand them"

Murray Brewster · CBC News · Posted: Jun 18, 2020 4:00 AM ET | Last Updated: 1 hour ago"

A well-written article by Mr. Brewster with perhaps some new info for us non-rotary wing types.

https://www.cbc.ca/news/politics/cyclone-chopper-helicopter-crash-fly-by-wire-1.5616809

Generally on point, relying heavily on Shawn Coyle’s expertise (definitely a good thing), but still some inaccuracies and/or omissions:

1. Sikorsky does have previous FBW experience. It worked with Boeing jointly in the cancelled RAH-66 Comanche program. Boeing leveraged that FBW experience into the Bell-Boeing V-22 Osprey program and Bell subsequently applied that jointly with AgustaWestland to the AB-609 tilt rotor (that become the Leonardo AW-609) and it’s own V-280 Valor tilt rotor. It would have been good to see a link to what if any transfer of FBW had occurred internally at Sikorsky from the RAH-66 to the H-92/CH-148;

2.  For what Mr. Brewster was trying to achieve, which I believe was a critical look at the program, it seemed appropriate to look further back in the article than the Conservative government’s 2015 formal decision to retire the CH-124A Sea King, particularly the Liberal government’s 2004/2005 decision to proceed with the H-92 as a developmental aircraft than the EH-101 Merlin production aircraft; and

3.  A Flight Director capability is not just a FBW thing, the Chinook, Cormorant and Griffon all have flight directors as well that couple the flight controls to various degrees.  Various autopilot modes fundamentally aren’t new, even if the implementation/platform specifics are.

Regards
G2G
 

Eye In The Sky

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Article Link

On June 18, 2020, the Office of the Chief Coroner for Ontario identified the remains of four of the six Canadian Armed Forces (CAF) members killed in the CH-148 Cyclone helicopter crash of April 29.

Remains of the following CAF members have been positively identified:

Captain Kevin Hagen, Pilot, originally from Nanaimo, British Columbia  :cdnsalute:

Captain Maxime Miron-Morin, Air Combat Systems Officer, originally from Bécancour, Quebec  :cdnsalute:

Sub-Lieutenant Matthew Pyke, Naval Warfare Officer, originally from Truro, Nova Scotia  :cdnsalute:

Master Corporal Matthew Cousins, Airborne Electronic Sensor Operator, originally from Guelph, Ontario  :cdnsalute:

Their remains were located and recovered during a combined CAF-United States Navy search and recovery operation conducted between May 25 and June 2. The families of all crew members lost in the accident have been notified.

Remains of Sub-Lieutenant Abbigail Cowbrough, a Marine Systems Engineering Officer originally from Toronto, Ontario, were previously identified shortly after the accident. Partial remains of Captain Brenden MacDonald, a Pilot originally from New Glasgow, Nova Scotia, were originally identified on May 9; no further remains were found in the recovery operations.

Over the coming days, our fallen who have now been positively identified, will be released to the families so they can be brought home. Ceremonial arrangements are being planned by the Royal Canadian Navy and Royal Canadian Air Force in consultation with the families, and will be communicated when available.

** I realize this is already posted in Thoughts and Prayers;  details of the REPAT will be coming shortly.
 

Colin Parkinson

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Cyclone hot loads a training torpedo during Rimpac
https://twitter.com/RoyalCanNavy/status/1295678418562973697
 

OceanBonfire

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dangerboy

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The Airworthiness Investigative Authority for the CAF has concluded its flight safety investigation into the accident that occurred on April 29, 2020 in the Ionian Sea involving a CH-148 Cyclone helicopter that claimed the lives of six CAF members. Report | CH148822 Cyclone - Epilogue
 

daftandbarmy

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The Airworthiness Investigative Authority for the CAF has concluded its flight safety investigation into the accident that occurred on April 29, 2020 in the Ionian Sea involving a CH-148 Cyclone helicopter that claimed the lives of six CAF members. Report | CH148822 Cyclone - Epilogue

I have a question but I am ignorant of the ways of things that fly, amongst many other things, so bear with me:

Why would we continue to fly this aircraft given it's 'fatal auto-pilot thingy' flaws? Should we rename the auto-pilot to HAL 9000?


Canadian Forces pilots not warned about autopilot before deadly Cyclone crash in 2020​

BY MICHAEL TUTTON, THE CANADIAN PRESS
Posted Jun 25, 2021 12:53 pm MDT

Last Updated Jun 25, 2021 at 1:04 pm MDT


HALIFAX — As a pilot guided one of Canada’s navy helicopters up into a tight turn, neither his training nor cockpit indicators warned of how a built-in autopilot would take control and plunge the Cyclone into the Ionian Sea, a military report has concluded.
All six Canadian Forces members on board died in the crash on April 29, 2020.

According to a board of inquiry report obtained by The Canadian Press, when the pilot was flying the turn, commonly called a “return to target,” he had pointed the nose up and used his feet to turn the helicopter’s tail, overriding the autopilot to complete the manoeuvre of less than 20 seconds.

The report, however, said testing wasn’t done during the aircraft’s certification to identify what would happen if a pilot overrode the autopilot more than “momentarily” and in certain complex situations. “The automation principles and philosophy that governed the Cyclone’s … design never intended for the (autopilot) to be overridden for extended periods of time, and therefore this was never tested,” it said.


This was the case even though — as the report stated — pilots are known on occasion to override the autopilot system without manually pressing a button on their control stick, called the cyclic.

The report said that at the time of the crash, the autopilot — referred to as the flight director — was set to an air speed of about 260 kilometres per hour before one of the pilots pitched the aircraft’s nose upward for the turn.

It was supposed to fly back over HMCS Fredericton and practise hoisting people onto the deck. Instead, the frigate’s CH-148 Cyclone helicopter crashed off the coast of Greece while returning from a NATO training mission. That crash caused the worst single-day loss of life for the Canadian Armed Forces since six soldiers were killed in a roadside bombing in Afghanistan on July 4, 2007.

The report indicated the crash might have been averted if the pilot had manually chosen to turn off the autopilot during the turn. But it also stated that it wasn’t unusual for pilots to override the autopilot and there were no explicit instructions in the manuals on the necessity to manually turn off the flight director.

In addition, the report said the pilot appeared unaware the computer would attempt to regain control near the end of the turn.

When the helicopter flipped around, the report said, the pilot pulled back as far as he could on the cyclic, attempting to right the aircraft that the computer was flying into the sea. Within seconds, the helicopter hit the ocean at massive force.

The board of inquiry said it found no evidence the flying pilot recognized he had lost control of the aircraft until it was too late.

Critical to the crash, the report said, was the aircraft’s software, which was certified by the military. If the autopilot is overridden, the computer accumulates digital commands, referred to as “command bias accumulation.” The more commands a pilot sends manually to the computer while the aircraft is coupled with the autopilot, the more this bias accumulation occurs, the report said.

After a pilot overrides the air speed set by the autopilot, a “feed forward look” occurs, the report said, adding that in some situations, “the pilot’s ability to control the aircraft … will be reduced or lost.”

The board of inquiry said the pilots’ training didn’t cover “with sufficient detail” certain risks of flying the aircraft, leaving the flyers unaware the autopilot would seek to keep control of the helicopter.

The return-to-target manoeuvre, which led to the crash, was being flown by others in the maritime helicopter community, the report said. That manoeuvre has been disallowed since the crash.

The report makes six recommendations, five of which involve better training for pilots to make them aware of the potential problems that could occur if they override the autopilot. It recommended creating special cockpit signals pilots could use to warn each other about overriding flight directors for extended periods of time.

The report also recommended the military consider an engineering change “to automatically disengage the flight director under certain conditions, such as when the flight director is overridden in multiple axes, or for an extended period of time.”

According to a senior military source, that recommendation is not shared in a second, independent report by the military’s Directorate of Flight Safety, expected to be released next week.

The second report said pilots must be well trained to almost instantly press a single button on their control stick to disengage the autopilot if they’re not getting the response they want out of their controls. It said, however, that automatically disengaging the autopilot might pose its own risks in some situations, especially when a pilot believes the autopilot will keep functioning.

The second report instead argued that the software — and its “bias accumulation” — needs to be addressed by American aviation company Sikorsky Aircraft, the manufacturer of the Cyclone.

“We need to look at that software … and see if we can eliminate this from the software altogether, being careful to understand when you make any changes like that you may introduce a butterfly effect and cause problems elsewhere,” the source said.

The board of inquiry report, signed by three members of the panel on Nov. 20, 2020, concluded the pilots were not distracted and the crew “flew well together.” It added that the aircraft captain had a strong command of the helicopter and the co-pilot showed “good situational awareness” throughout the mission.

The second report is expected to provide further analysis on the factors behind the crash.

The military source said the recommendations of the two reports must be meshed into a single set of findings for consideration by senior Royal Canadian Air Force officers.

A spokeswoman for Sikorsky referred all questions on the report to the Canadian Forces.

 

kev994

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The problem was they were essentially hand flying but with the autopilot engaged (they’re overriding it). The autopilot isn’t an issue if you don’t do that.
 

Good2Golf

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D&B, some autopilots (AP, an oversimplified term, TBH) allow pilots to override/fly-through/manually adjust/etc., but how the AP reacts can vary greatly, ranging from: disengage; to pause until pilot input ceases; to operate while blending pilot input; to operate while applying reduced pilot input; to ignoring pilot input unless the pilot temporarily or permanently suspends AP function.

Furthermore, there can be several ‘levels’ of AP function, ranging from ever-present stability input of flight controls up to multi-axis flight director/coupled flight control input.

Add further to that the additional factor that the AP may have varying degrees of ‘authority’ (degree to which the AP can alter flight controls, relative to pilot’s full extent of moving the controls) with most APs on mechanical/hydraulic flight controls having a minority percentage authority (typically teens-to-20s% authority) leading to digital fly-by-wire flight control systems (like the Cyclone has, or Airbus airliners have, etc.) where an AP could have up to 100% authority (ie. totally override any manual control input).

Now, don’t tell the pilots how manual override of a coupled mode of the AP fully works, nor if there are modes specifically avoid due to the AP mode and control authority (eg. like the command bias accumulation effect that the Cyclone’s AP was using to fight the pilot’s manual input), and the holes in the Swiss cheese accident model start to line up towards an unfortunate end.

It’s not the first time that a manufacturer’s flight control software programmers programmed what they thought made sense and what the operators wanted (or may have specified or failed to specify so a default was assumed), that resulted in an accident (eg. first A320 crash, 737-MAX, CH-148), but it likely won’t be the last, either.

With automation, the good thing is that aircraft can do some pretty extreme things, but the bad thing is that aircraft can do some pretty extreme things…

Sadly, in the case of STALKER 22, take all that stuff above, and in single-digits of seconds as you’re descending at high speed towards the water and the controls aren’t responding the way you expect them to (not were ever provided information that such a situation could develop), the outcome isn’t good. 😔

Regards
G2G
 

SeaKingTacco

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D&B, some autopilots (AP, an oversimplified term, TBH) allow pilots to override/fly-through/manually adjust/etc., but how the AP reacts can vary greatly, ranging from: disengage; to pause until pilot input ceases; to operate while blending pilot input; to operate while applying reduced pilot input; to ignoring pilot input unless the pilot temporarily or permanently suspends AP function.

Furthermore, there can be several ‘levels’ of AP function, ranging from ever-present stability input of flight controls up to multi-axis flight director/coupled flight control input.

Add further to that the additional factor that the AP may have varying degrees of ‘authority’ (degree to which the AP can alter flight controls, relative to pilot’s full extent of moving the controls) with most APs on mechanical/hydraulic flight controls having a minority percentage authority (typically teens-to-20s% authority) leading to digital fly-by-wire flight control systems (like the Cyclone has, or Airbus airliners have, etc.) where an AP could have up to 100% authority (ie. totally override any manual control input).

Now, don’t tell the pilots how manual override of a coupled mode of the AP fully works, nor if there are modes specifically avoid due to the AP mode and control authority (eg. like the command bias accumulation effect that the Cyclone’s AP was using to fight the pilot’s manual input), and the holes in the Swiss cheese accident model start to line up towards an unfortunate end.

It’s not the first time that a manufacturer’s flight control software programmers programmed what they thought made sense and what the operators wanted (or may have specified or failed to specify so a default was assumed), that resulted in an accident (eg. first A320 crash, 737-MAX, CH-148), but it likely won’t be the last, either.

With automation, the good thing is that aircraft can do some pretty extreme things, but the bad thing is that aircraft can do some pretty extreme things…

Sadly, in the case of STALKER 22, take all that stuff above, and in single-digits of seconds as you’re descending at high speed towards the water and the controls aren’t responding the way you expect them to (not were ever provided information that such a situation could develop), the outcome isn’t good. 😔

Regards
G2G
Pretty much what G2G just said. Both training and documentation has been improved since the accident.
 

daftandbarmy

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D&B, some autopilots (AP, an oversimplified term, TBH) allow pilots to override/fly-through/manually adjust/etc., but how the AP reacts can vary greatly, ranging from: disengage; to pause until pilot input ceases; to operate while blending pilot input; to operate while applying reduced pilot input; to ignoring pilot input unless the pilot temporarily or permanently suspends AP function.

Furthermore, there can be several ‘levels’ of AP function, ranging from ever-present stability input of flight controls up to multi-axis flight director/coupled flight control input.

Add further to that the additional factor that the AP may have varying degrees of ‘authority’ (degree to which the AP can alter flight controls, relative to pilot’s full extent of moving the controls) with most APs on mechanical/hydraulic flight controls having a minority percentage authority (typically teens-to-20s% authority) leading to digital fly-by-wire flight control systems (like the Cyclone has, or Airbus airliners have, etc.) where an AP could have up to 100% authority (ie. totally override any manual control input).

Now, don’t tell the pilots how manual override of a coupled mode of the AP fully works, nor if there are modes specifically avoid due to the AP mode and control authority (eg. like the command bias accumulation effect that the Cyclone’s AP was using to fight the pilot’s manual input), and the holes in the Swiss cheese accident model start to line up towards an unfortunate end.

It’s not the first time that a manufacturer’s flight control software programmers programmed what they thought made sense and what the operators wanted (or may have specified or failed to specify so a default was assumed), that resulted in an accident (eg. first A320 crash, 737-MAX, CH-148), but it likely won’t be the last, either.

With automation, the good thing is that aircraft can do some pretty extreme things, but the bad thing is that aircraft can do some pretty extreme things…

Sadly, in the case of STALKER 22, take all that stuff above, and in single-digits of seconds as you’re descending at high speed towards the water and the controls aren’t responding the way you expect them to (not were ever provided information that such a situation could develop), the outcome isn’t good. 😔

Regards
G2G

Now my head hurts. And I think I get it. All at once.

Thanks!!
 

Loachman

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The min requirements were somewhat more.

I always found IF interesting, but not something that I would consider doing recreationally.

Most of my flying time was fully manual - Mouseketeer, Tutor, Jet Ranger (Military and Police), and Kiowa - and looking where I was going.

And I was never a "146 guy". I just flew it because the better helicopter was retired.
 
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