AS332L2 Ditching off Shetland: 23rd August 2013
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Hi Crab, with the V/S installed in 3 axis mode it is active on the Cyclic "Pitch" channel. I was fairly certain they had set an ALT.A at MDA.
The incipient reduction in IAS during the descent would have been small compared to the effect when the ALT engaged automatically at the MDA.
During our L2 Type Training at the same Operator, the Training Staff went to great lengths to demonstrate this effect to us to dissuade us from engaging in this potentially dangerous practice,. We called it "The L2 tail slide" as that is what it felt like at the extreme.
As an aside, the PM took a hit for not monitoring the IAS. However, at the point of level off at MDA, the PF should be primarily monitoring the Instruments and the PM looking out for the Required Visual References. It raises an interesting argument and further supports the practice of CDFA where there is no level off and therefore no prolonged attempt to gain visual references and thus less opportunity to lose the IAS.
This single accident raised a lot of issues. All inter related and all significant.
The incipient reduction in IAS during the descent would have been small compared to the effect when the ALT engaged automatically at the MDA.
During our L2 Type Training at the same Operator, the Training Staff went to great lengths to demonstrate this effect to us to dissuade us from engaging in this potentially dangerous practice,. We called it "The L2 tail slide" as that is what it felt like at the extreme.
As an aside, the PM took a hit for not monitoring the IAS. However, at the point of level off at MDA, the PF should be primarily monitoring the Instruments and the PM looking out for the Required Visual References. It raises an interesting argument and further supports the practice of CDFA where there is no level off and therefore no prolonged attempt to gain visual references and thus less opportunity to lose the IAS.
This single accident raised a lot of issues. All inter related and all significant.
This single accident raised a lot of issues. All inter related and all significant.
Personally I dislike CDFA profiles - may be my age - but the ability to level off at MDA and run in until the MAPt is ideally suited to helicopters in marginal conditions.
The fact that they managed the 'L2 tail slide' without using ALT.A speaks volumes for the lack of CRM.
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You have to remember, the L2 was a very early first generation glass cockpit helicopter and coupler.
Compared to anything else I’d flown before, it was without doubt the best thing since sliced bread.
Treated with respect the 3 axis AP function was more than adequate
Like any other it did have vices which could jump up and bite.
The vertical bar indication for IAS was difficult and non intuitive
Thankfully with time progress has been made with AP flight envelope protection
Compared to anything else I’d flown before, it was without doubt the best thing since sliced bread.
Treated with respect the 3 axis AP function was more than adequate
Like any other it did have vices which could jump up and bite.
The vertical bar indication for IAS was difficult and non intuitive
Thankfully with time progress has been made with AP flight envelope protection
Despite DBs assertions that the L2 AP was great, that wasn't a view shared by the majority of line pilots. The collective coupling was very slow to react to required changes and then had a habit of overreacting in an attempt to play "catch-up" and could cause momentary overtorques. As the data in the AAIB report indicates, most crews would chose not to use the collective channel i.e. only use 3 axis coupling.
The choice of 3 axis rather than 4 axis coupling wasn't itself a fundamental mistake, it was the choice to couple altitude to pitch rather than speed. The lack of speed monitoring at 80 KIAS and below was the final hole in the Emmental.
The choice of 3 axis rather than 4 axis coupling wasn't itself a fundamental mistake, it was the choice to couple altitude to pitch rather than speed. The lack of speed monitoring at 80 KIAS and below was the final hole in the Emmental.
it was the choice to couple altitude to pitch rather than speed.
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Ok. If it was widely understood and accepted, as evidenced, that most pilots would choose to fly an approach in the L2 with only 3-axes engaged, as the AP struggled in 4-axes, I'm imagining that the 6 monthly training and checking would also have reflected that.
Leaving manually flown approaches aside, if it was standard practice to fly a coupled approach with only 3-axes engaged, knowing the risks associated with this, it must have become part of routine training to demonstrate the dangers and regularly check competency in this DEGRADED mode. What benefit would be gained from successfully completing a 4-axes approach in the sim if it did not match the reality of how the aircraft was operated?
Risk assessment + mitigation through SOP + training needs analysis + demonstration and practice + assessment = role competent pilot / crew.
To pinch a line from a colleague, "Why do good pilots make poor choices?" - generally, not knowingly.
Leaving manually flown approaches aside, if it was standard practice to fly a coupled approach with only 3-axes engaged, knowing the risks associated with this, it must have become part of routine training to demonstrate the dangers and regularly check competency in this DEGRADED mode. What benefit would be gained from successfully completing a 4-axes approach in the sim if it did not match the reality of how the aircraft was operated?
Risk assessment + mitigation through SOP + training needs analysis + demonstration and practice + assessment = role competent pilot / crew.
To pinch a line from a colleague, "Why do good pilots make poor choices?" - generally, not knowingly.
Last edited by marcr; 19th Sep 2020 at 13:21. Reason: Add emphasis.
Originally Posted by [email protected]
or rather to ask the AP to use the cyclic channel to control RoD (VS) leaving the pilot in the counter-intuitive position of controlling speed with collective.
They didn't have ALT.A coupled according to the report, just VS. Unless I have read it wrong.
I was trying to clarify the phrase 'coupling to pitch' since it could be pitch channel, pitch attitude or collective pitch.
I was trying to clarify the phrase 'coupling to pitch' since it could be pitch channel, pitch attitude or collective pitch.
Originally Posted by [email protected]
They didn't have ALT.A coupled according to the report, just VS. Unless I have read it wrong.
I was trying to clarify the phrase 'coupling to pitch' since it could be pitch channel, pitch attitude or collective pitch.
I was trying to clarify the phrase 'coupling to pitch' since it could be pitch channel, pitch attitude or collective pitch.
.As for coupling modes, I've always talked about the principal axes of motion as being pitch, roll and yaw. A certain French manufacturer does confuse things by having blade pitch as a fundamental measure of collective application, but I dismiss such things as an aberration of poor judgement and odd Gallic tendencies
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VR your memory is not clear. The L2 was powerprotected in all coupled modes with the sole exception of CRHT. Height Capture. Which, in our outfit, was mandated not to be used. Other than this, in 4K hrs offshoreL2 I never experienced poor AP performance. There are limits, well documented in the AFM. Operations outside those limits could be exciting.......but until APM 2000 came along, the L2 AP was far better than most of the alternatives.
We regularly and routinely flew approaches in 4 axis. Oddly. We cruised in 3 axis mode to reduce the power modulations in turbulence etc.
We regularly and routinely flew approaches in 4 axis. Oddly. We cruised in 3 axis mode to reduce the power modulations in turbulence etc.
VL - I get where you are coming from - on the Mk3A Sea King we had an SN500 duplex AP, when selecting TAS hold for example, the PF would acknowledge coupled in pitch, that was why I wanted to clarify the term - coupled in Pitch or Roll or Yaw is quite specific to the AP channel, coupled to pitch is more ambiguous.
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Originally Posted by [email protected]
VL - I get where you are coming from - on the Mk3A Sea King we had an SN500 duplex AP, when selecting TAS hold for example, the PF would acknowledge coupled in pitch, that was why I wanted to clarify the term - coupled in Pitch or Roll or Yaw is quite specific to the AP channel, coupled to pitch is more ambiguous.
Channel - PITCH about the lateral axis.
Channel - ROLL around the Longitudinal axis
Channel - YAW around the Normal axis.
These are Attitude modulations.
The commanded collective channel does not create attitude changes (intentionally) and is the oddity.
I didn't think it was confusing, just a terminology question.
On the subject of manual flying skills and training, this is an issue that I finally managed to rectify in our company for the 225, shortly before I retired. It was a struggle though! Basic problem is that for 6 monthly checks, the rules said that you must fly manual approaches. That is, approaches with full autopilot functionality in terms of attitude hold when cyclic release, artificial stability when cyclic operated, co-ordinated turn, heading hold when wings level etc. But not allowed to use the upper modes. Crazy, because that scenario is just about impossible.
So a lot of training time had, by CAA edict, to be spent manually flying. So no time left to properly explore how best to use the automation, how to deal with partial automation etc. Crazy! The whole industry, including the CAA, is culpable for this accident. But unfortunately they get away with it and just blame the pilots.
As I mentioned I finally persuaded CAA to allow fully coupled approaches by default for OPC /LPC, albeit with some partial (and hence realistic) malfunction thrown in for one of the approaches. It is just crazy to train for stuff that you never have to do in reality, and to not train for the stuff that is your bread and butter. And to take the view that certainly prevailed at the time with CAA and EASA - that real pilots flew manually, anyone using the coupled modes was cheating.
Been away for 7 years now, it would be great to think things had changed a bit but I rather doubt it!
Oh and in summary, they should have been using IAS mode. Maybe with Vs on collective, or not, doesn’t matter too much but the key thing was to have IAS engaged. If they had done that, the accident wouldn’t have happened. But nothing in CHC ops man at the time that told them what to engage or the perils of not engaging IAS.
So a lot of training time had, by CAA edict, to be spent manually flying. So no time left to properly explore how best to use the automation, how to deal with partial automation etc. Crazy! The whole industry, including the CAA, is culpable for this accident. But unfortunately they get away with it and just blame the pilots.
As I mentioned I finally persuaded CAA to allow fully coupled approaches by default for OPC /LPC, albeit with some partial (and hence realistic) malfunction thrown in for one of the approaches. It is just crazy to train for stuff that you never have to do in reality, and to not train for the stuff that is your bread and butter. And to take the view that certainly prevailed at the time with CAA and EASA - that real pilots flew manually, anyone using the coupled modes was cheating.
Been away for 7 years now, it would be great to think things had changed a bit but I rather doubt it!
Oh and in summary, they should have been using IAS mode. Maybe with Vs on collective, or not, doesn’t matter too much but the key thing was to have IAS engaged. If they had done that, the accident wouldn’t have happened. But nothing in CHC ops man at the time that told them what to engage or the perils of not engaging IAS.
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HC I agree with much of your post but would caution that it is unfair to blame CAA and the regulators in general. The experts in these areas were in fact us. The Industry. In hindsight types where failure of the upper modes or indeed, the AFCS were reasonably expected, it was prudent to practise manually flown procedures. However, it took us all a while to realise that these policies were not suitable once the full digital age had arrived. You were undoubtedly a key voice in this change. I think it is important to understand that the regulator is simply a mirror, reflecting back what happens in the industry.
Still I feel EASA have missed the boat on this one. I am obliged to cover vortex ring and settling with power at each OPC/LPC when I feel much more should be made of the incipient hazards of poor application of automation. Just look at the many pages in the regs prescribing FW LOC (Upset) training. Nothing in there about helicopter AFCS except a few headline policy requirements.
We are in a better place than 10-15 years ago. However it has taken that time for us all to better understand how to fully exploit the new technology. I think we are still learning.
it is often much more beneficial to demonstrate to crews poor technique than to simply demand they apply the correct one.
Still I feel EASA have missed the boat on this one. I am obliged to cover vortex ring and settling with power at each OPC/LPC when I feel much more should be made of the incipient hazards of poor application of automation. Just look at the many pages in the regs prescribing FW LOC (Upset) training. Nothing in there about helicopter AFCS except a few headline policy requirements.
We are in a better place than 10-15 years ago. However it has taken that time for us all to better understand how to fully exploit the new technology. I think we are still learning.
it is often much more beneficial to demonstrate to crews poor technique than to simply demand they apply the correct one.
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DB - "This single accident raised a lot of issues. All inter related and all significant."
HeliComparator - "The whole industry, including the CAA, is culpable for this accident."
Thank you both.
Telling the pilots what they "should have been doing" is the easy part.
Dealing with what got us to this point, is a task that demands attention and begs greater engagement from us all - and across the board. It is not of huge benefit if the "joined up" response at executive level only serves to create an illusion of progress, when very little has actually changed for the crews. How many North Sea pilots have even seen the FCOM for their aircraft?
As for the CAA. I think it is fair to include the organisation as a contributing factor. "Light touch" regulation just doesn't work. If expert help is needed - get it.
There are more avoidable accidents waiting to happen - who will we be trying to blame the next time?
HeliComparator - "The whole industry, including the CAA, is culpable for this accident."
Thank you both.
Telling the pilots what they "should have been doing" is the easy part.
Dealing with what got us to this point, is a task that demands attention and begs greater engagement from us all - and across the board. It is not of huge benefit if the "joined up" response at executive level only serves to create an illusion of progress, when very little has actually changed for the crews. How many North Sea pilots have even seen the FCOM for their aircraft?
As for the CAA. I think it is fair to include the organisation as a contributing factor. "Light touch" regulation just doesn't work. If expert help is needed - get it.
There are more avoidable accidents waiting to happen - who will we be trying to blame the next time?
Surely it rather begs the question what is the point of the regulator, if they take their lead from the status quo and from those they are supposed to be regulating?
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Enquiry ends...
There was a 5th victim...
What a sad case...
An offshore helicopter crash in which four people died was caused by pilot error, an inquiry has ruled.
Sheriff Principal Derek Pyle said the Super Puma had not maintained the correct speed as it approached its landing in Shetland in 2013.
He said the reason for the error remained unknown - but that there had been "no wilful neglect" by the pilot.
A total of 18 people were on board when the helicopter hit the sea on its approach to Sumburgh.
The Super Puma overturned and filled with water, but it did not sink due to its flotation devices.
Sarah Darnley, 45, from Elgin; Duncan Munro, 46, from Bishop Auckland; and George Allison, 57, of Winchester, drowned in the accident.
Gary McCrossan, 59, from Inverness, who had cardiac disease, died from heart failure following the crash.
The inquiry also heard that one survivor, Sam Bull, took his own life four years later aged 28 after suffering post-traumatic stress disorder (PTSD).
Pilot Martin Miglans and co-pilot Alan Bell were among those who escaped.
Sheriff Principal Derek Pyle said the Super Puma had not maintained the correct speed as it approached its landing in Shetland in 2013.
He said the reason for the error remained unknown - but that there had been "no wilful neglect" by the pilot.
A total of 18 people were on board when the helicopter hit the sea on its approach to Sumburgh.
The Super Puma overturned and filled with water, but it did not sink due to its flotation devices.
Sarah Darnley, 45, from Elgin; Duncan Munro, 46, from Bishop Auckland; and George Allison, 57, of Winchester, drowned in the accident.
Gary McCrossan, 59, from Inverness, who had cardiac disease, died from heart failure following the crash.
The inquiry also heard that one survivor, Sam Bull, took his own life four years later aged 28 after suffering post-traumatic stress disorder (PTSD).
Pilot Martin Miglans and co-pilot Alan Bell were among those who escaped.
What a sad case...
Sam Bull was one of the first of the survivors to escape from a submerged helicopter after it crashed into the North Sea off Shetland.
He helped with the life rafts, and tried to resuscitate one of his fellow passengers - although those efforts would prove to be in vain.
The man he tried to save was one of four people who lost their lives on the day of the crash in August 2013.
Sam was haunted by the harrowing events. Four years later, at the age of 28, he took his own life after suffering post-traumatic stress disorder (PTSD).
As the findings of a fatal accident inquiry are published, Sam's father Michael spoke to BBC Scotland News in the hope of raising awareness of the impact that trauma can have on people.
He helped with the life rafts, and tried to resuscitate one of his fellow passengers - although those efforts would prove to be in vain.
The man he tried to save was one of four people who lost their lives on the day of the crash in August 2013.
Sam was haunted by the harrowing events. Four years later, at the age of 28, he took his own life after suffering post-traumatic stress disorder (PTSD).
As the findings of a fatal accident inquiry are published, Sam's father Michael spoke to BBC Scotland News in the hope of raising awareness of the impact that trauma can have on people.