AS332L2 Ditching off Shetland: 23rd August 2013
Join Date: Aug 2001
Location: Cornwall
Age: 75
Posts: 1,307
Likes: 0
Received 0 Likes
on
0 Posts
We can be our own worst enemies....
.... when we train and rehearse scenarios that we use on a frequent basis. The fourth phase in the classic four-stage learning model (see below) leaves us exposed to the vagaries of 'unconscious competence'. This is clearly demonstrated when we drive our well worn route to work and upon arrival cannot remember vital details of the journey.
The role of the PM is critical in this respect but in the helicopter world we do not appear to take this role as seriously as we should.
In the FW (airline) world the LPC/OPC examiner will occupy the PF seat for a portion of the flight and 'seed' it with errors requiring intervention by the PM. That then leads to an assessment of his capabilities in the PM role. Does anyone in the RW world use such a system?
The four stages of learning -
1. UNCONSCIOUS INCOMPETENCE - The subject is not aware that he/she needs the knowledge/skill on offer or believes that in his/her case it is unnecessary.
2. CONSCIOUS INCOMPETENCE - The subject now recognises that the skill/knowledge is indeed required and sets about acquiring/understanding it.
3. CONSCIOUS COMPETENCE - The subject now knows what to do and how to do it and carefully applies that knowledge/skill.
4. UNCONSCIOUS COMPETENCE - The skill/knowledge is so well practiced that the task can be accomplished without conscious thought or monitoring.
The role of the PM is critical in this respect but in the helicopter world we do not appear to take this role as seriously as we should.
In the FW (airline) world the LPC/OPC examiner will occupy the PF seat for a portion of the flight and 'seed' it with errors requiring intervention by the PM. That then leads to an assessment of his capabilities in the PM role. Does anyone in the RW world use such a system?
The four stages of learning -
1. UNCONSCIOUS INCOMPETENCE - The subject is not aware that he/she needs the knowledge/skill on offer or believes that in his/her case it is unnecessary.
2. CONSCIOUS INCOMPETENCE - The subject now recognises that the skill/knowledge is indeed required and sets about acquiring/understanding it.
3. CONSCIOUS COMPETENCE - The subject now knows what to do and how to do it and carefully applies that knowledge/skill.
4. UNCONSCIOUS COMPETENCE - The skill/knowledge is so well practiced that the task can be accomplished without conscious thought or monitoring.
Last edited by Geoffersincornwall; 23rd Mar 2016 at 09:50.
HC
Which one of the 'mistakes' do we put down to 'human fraility' - all of them?
Will the aftermath ensure that MPs ( co-pilot in this case) who will not say "boo to a ghost" are seriously reminded of their responsibilities or shown the door? Huge company culture scenario?
I 'killed' a v experienced instructor in the sim by deliberately crashing on approach to a rig - TWICE - and after him being reminded of his responsibilities before the exercise even began!
I am pretty sure this mistake would not have happened if the approach was able to be flown 'single-pilot'. Completely different mindset and not relying on loosely adhered too multi-pilot procedures.
Complacency due to routine/boredom/ego/over-familiarity - more human frailties - all we need to do now is take the human element out of it .............
Humans are not meant to fly but we insist on it and still pay 'lip service' to critical elements.
Which one of the 'mistakes' do we put down to 'human fraility' - all of them?
Will the aftermath ensure that MPs ( co-pilot in this case) who will not say "boo to a ghost" are seriously reminded of their responsibilities or shown the door? Huge company culture scenario?
I 'killed' a v experienced instructor in the sim by deliberately crashing on approach to a rig - TWICE - and after him being reminded of his responsibilities before the exercise even began!
I am pretty sure this mistake would not have happened if the approach was able to be flown 'single-pilot'. Completely different mindset and not relying on loosely adhered too multi-pilot procedures.
Complacency due to routine/boredom/ego/over-familiarity - more human frailties - all we need to do now is take the human element out of it .............
Humans are not meant to fly but we insist on it and still pay 'lip service' to critical elements.
EESDL
It's stating the obvious to say that the approach wasn't flown properly and that even in the absence of a better method of carring out the approach, it shouldn't have ended badly if either of the pilots had been alert to critical deviations. But the accident did play out as it did. And it isn't the first of it kind. So you have to look both at and beyond the failings of that crew in that situation.
Using VS rather than IAS for a single cue descent is something that I often see (where 4-axis is not available), and is in some company cultures the preferred method. I am personally leery of it because it is less intuitive with basic flying sklls (using PWR to manage ROD). Learning and culture...
Allowing yourself an approach below minima and acquiesence by the left seat? Culture? Probably not the only person on the forum who can think of examples like that.
No clear breifing and conducting the approach according to it? Culture.
Across companies it's pretty clear that rotary is still working its way towards standardisation and real MCC.
I agree with you that the accident probably wouldn't have happened if flown single pilot because the PF would not have been so complacent and taken the same risks.
Single cue descents need particular care and monitoring: It isn't an automated approach or a hands-flown approach, but a mix of both. In an age of automation, using less of the AFCS than you can, may well cause an expectation gap in the cockpit: How aware was the PM of what he should be expecting to see as the captain reduced speed? Neither pilot seemed to have any seat-of-the-pants awareness as they began to fall behind the power curve. Suggests to me that they were both off the page when the method required them to be absolutely on it.
TT
It's stating the obvious to say that the approach wasn't flown properly and that even in the absence of a better method of carring out the approach, it shouldn't have ended badly if either of the pilots had been alert to critical deviations. But the accident did play out as it did. And it isn't the first of it kind. So you have to look both at and beyond the failings of that crew in that situation.
Using VS rather than IAS for a single cue descent is something that I often see (where 4-axis is not available), and is in some company cultures the preferred method. I am personally leery of it because it is less intuitive with basic flying sklls (using PWR to manage ROD). Learning and culture...
Allowing yourself an approach below minima and acquiesence by the left seat? Culture? Probably not the only person on the forum who can think of examples like that.
No clear breifing and conducting the approach according to it? Culture.
Across companies it's pretty clear that rotary is still working its way towards standardisation and real MCC.
I agree with you that the accident probably wouldn't have happened if flown single pilot because the PF would not have been so complacent and taken the same risks.
Single cue descents need particular care and monitoring: It isn't an automated approach or a hands-flown approach, but a mix of both. In an age of automation, using less of the AFCS than you can, may well cause an expectation gap in the cockpit: How aware was the PM of what he should be expecting to see as the captain reduced speed? Neither pilot seemed to have any seat-of-the-pants awareness as they began to fall behind the power curve. Suggests to me that they were both off the page when the method required them to be absolutely on it.
TT
Came across this earlier, not sure if this has been discussed before.
https://www.expressandstar.com/news/...-inquiry-told/
Four people were killed when the Super Puma L2 ditched in the sea on its approach to Sumburgh Airport in Shetland in August 2013.
/cloudfront-us-east-1.images.arcpublishing.com/expressandstar.mna/KDT6SFE6MFFYZMAKK5ZJNAO7WM.jpg)
Shetland helicopter crash A helicopter which ditched in the sea with the loss of four lives would not have crashed if the pilot had stabilised the speed on approach to the airport, an inquiry has heard.
Mark Prior, an expert pilot, said that if the pilot had stabilised the speed at 80 knots he would have been able to level off and would not have ended up losing control of the aircraft.
Two crew members and 12 passengers on the Super Puma L2 survived when it ditched on its approach to Sumburgh Airport in Shetland at 6.17pm on August 23 2013.
But Sarah Darnley, 45, from Elgin, Moray; Gary McCrossan, 59, from Inverness; Duncan Munro, 46, from Bishop Auckland, County Durham, and George Allison, 57, from Winchester, Hampshire, died.
An AAIB report published in 2016 found that the pilots failed to properly monitor the flight instruments and failed to notice their speed was decreasing until it was too late to avoid the helicopter plunging into the sea.
Crown witness Mr Prior, a private aviation consultant who previously worked for the RAF for 40 years, prepared a report on the crash with three other pilot experts for the Fatal Accident Inquiry (FAI), which is being held virtually due to coronavirus measures.
There was still an issue due to the autopilot configuration, it would have been difficult to level, but, that point aside, they would have had enough energy to level off and perhaps commence a missed approach
Aviation consultant Mark PriorSheriff Principal Derek Pyle, who is leading the inquiry, said: “What we know is, at some later point, the aircraft got down to the correct speed of 80 knots and that was more than two miles from Sumburgh Airport.
“In the event that the pilot who apparently said just after that point ‘Right that’s 80 knots, that’ll do’, if the pilot had then stabilised the speed at 80 knots would the accident have occurred?”
Mr Prior replied: “In my opinion no, because if they had flown at 80 knots that would have allowed them to continue. There was still an issue due to the autopilot configuration, it would have been difficult to level, but, that point aside, they would have had enough energy to level off and perhaps commence a missed approach.
“Certainly they would not have been in a regime of flight where the manual handling of the aircraft became more difficult and in the end they lost control.”
The inquiry heard that later in the flight the air speed dropped from 70 knots to 35 knots over around 23 seconds and then crashed
Mr Prior said he did not believe the crew scanned the instruments effectively during those 23 seconds because they had not noticed the drop in speed.Asked what would have happened if this performance had been replicated in tests for an examination, he replied: “They would certainly have failed the test.”
Mr Prior said both the pilot flying (PF) and pilot non-flying (PNF) had responsibility for monitoring the air speed, though the PF had “more weight” in the role as the PNF had other tasks to carry out.
Victims Duncan Munro, George Allison, Gary McCrossan and Sarah Darnley (Police Scotland/PA)He told the inquiry that by the time the crew noticed the airspeed, when the helicopter was below 300 feet, it was “too late” to recover the aircraft.
Martin Richardson QC, who is leading the inquiry for the Crown, asked which factors he considered particularly relevant to the cause of the accident.
Mr Prior said the accident followed a chain of events including the fact that if the crew had been aware of the weather before they set off they might have made different decisions.
He told the FAI: “Having commenced this approach, the major factors, I believe, are the fact that they did not achieve a stable approach, and because they did not achieve a stable approach that made them more prone to any errors in scanning, and so the secondary factor here is that the crew did not see the change in the air speed, they did not see the nose pitching up and they did not see the low power set.”
Mr Prior also told the inquiry that the lack of a stabilised approach meant they were not compliant with the operations manual.
Mr Richardson asked about the training given to crew and passengers in relation to ditching, with Mr Prior saying his training in France was “a very realistic test” compared with the UK training.
He said: “The French like to have a cold pool, you are wearing just a thin cotton flying suit, and it is a very realistic test.
“The second you go into the water, you shiver and gasp. You don’t have a briefing beforehand. You have to immerse yourself completely for a minute, then swim along a rope and do all of these types of tasks.
“You were then dunked into the cold water in the dunker, you were not allowed to escape until you were tapped on the shoulder by a diver. It was a very long pause and you had to wait until your breath was about to run out and then escape.
“As a young, fit military pilot, I found that a very demanding task, but you could say that was the most realistic training I’d had.”
He said in the UK, the pool is reasonably warm, and you are given a thorough briefing before.
Having completed the same training that offshore workers received, Mr Prior said: “To have a reasonably warm pool is false, but if you are teaching people how to escape, you don’t want their first instinct to be to panic as they descend – so there’s a balance to strike between the realism of the training and the training itself.
“I believe if most people had to go through the French training, they would not choose to go offshore.”
Survivor Samuel Bull took his own life in London in 2017, which Sheriff Pyle said was “directly caused” by the crash.
The inquiry is being held virtually due to coronavirus measures.
A statement of agreed evidence read at the start of the inquiry confirmed that no mechanical fault was discovered with the helicopter, which was returning from the Borgsten Dolphin support vessel to Sumburgh Airport when it ditched.
The inquiry continues.
UK News
https://www.expressandstar.com/news/...-inquiry-told/
Helicopter would not have crashed if pilot had stabilised speed, inquiry told
UK News | Published: Sep 11, 2020 | Last Updated: 21 hours agoFour people were killed when the Super Puma L2 ditched in the sea on its approach to Sumburgh Airport in Shetland in August 2013.
Shetland helicopter crash A helicopter which ditched in the sea with the loss of four lives would not have crashed if the pilot had stabilised the speed on approach to the airport, an inquiry has heard.Mark Prior, an expert pilot, said that if the pilot had stabilised the speed at 80 knots he would have been able to level off and would not have ended up losing control of the aircraft.
Two crew members and 12 passengers on the Super Puma L2 survived when it ditched on its approach to Sumburgh Airport in Shetland at 6.17pm on August 23 2013.
But Sarah Darnley, 45, from Elgin, Moray; Gary McCrossan, 59, from Inverness; Duncan Munro, 46, from Bishop Auckland, County Durham, and George Allison, 57, from Winchester, Hampshire, died.
An AAIB report published in 2016 found that the pilots failed to properly monitor the flight instruments and failed to notice their speed was decreasing until it was too late to avoid the helicopter plunging into the sea.
Crown witness Mr Prior, a private aviation consultant who previously worked for the RAF for 40 years, prepared a report on the crash with three other pilot experts for the Fatal Accident Inquiry (FAI), which is being held virtually due to coronavirus measures.
There was still an issue due to the autopilot configuration, it would have been difficult to level, but, that point aside, they would have had enough energy to level off and perhaps commence a missed approach
Aviation consultant Mark PriorSheriff Principal Derek Pyle, who is leading the inquiry, said: “What we know is, at some later point, the aircraft got down to the correct speed of 80 knots and that was more than two miles from Sumburgh Airport.
“In the event that the pilot who apparently said just after that point ‘Right that’s 80 knots, that’ll do’, if the pilot had then stabilised the speed at 80 knots would the accident have occurred?”
Mr Prior replied: “In my opinion no, because if they had flown at 80 knots that would have allowed them to continue. There was still an issue due to the autopilot configuration, it would have been difficult to level, but, that point aside, they would have had enough energy to level off and perhaps commence a missed approach.
“Certainly they would not have been in a regime of flight where the manual handling of the aircraft became more difficult and in the end they lost control.”
The inquiry heard that later in the flight the air speed dropped from 70 knots to 35 knots over around 23 seconds and then crashed
Mr Prior said he did not believe the crew scanned the instruments effectively during those 23 seconds because they had not noticed the drop in speed.Asked what would have happened if this performance had been replicated in tests for an examination, he replied: “They would certainly have failed the test.”
Mr Prior said both the pilot flying (PF) and pilot non-flying (PNF) had responsibility for monitoring the air speed, though the PF had “more weight” in the role as the PNF had other tasks to carry out.
Victims Duncan Munro, George Allison, Gary McCrossan and Sarah Darnley (Police Scotland/PA)He told the inquiry that by the time the crew noticed the airspeed, when the helicopter was below 300 feet, it was “too late” to recover the aircraft.Martin Richardson QC, who is leading the inquiry for the Crown, asked which factors he considered particularly relevant to the cause of the accident.
Mr Prior said the accident followed a chain of events including the fact that if the crew had been aware of the weather before they set off they might have made different decisions.
He told the FAI: “Having commenced this approach, the major factors, I believe, are the fact that they did not achieve a stable approach, and because they did not achieve a stable approach that made them more prone to any errors in scanning, and so the secondary factor here is that the crew did not see the change in the air speed, they did not see the nose pitching up and they did not see the low power set.”
Mr Prior also told the inquiry that the lack of a stabilised approach meant they were not compliant with the operations manual.
Mr Richardson asked about the training given to crew and passengers in relation to ditching, with Mr Prior saying his training in France was “a very realistic test” compared with the UK training.
He said: “The French like to have a cold pool, you are wearing just a thin cotton flying suit, and it is a very realistic test.
“The second you go into the water, you shiver and gasp. You don’t have a briefing beforehand. You have to immerse yourself completely for a minute, then swim along a rope and do all of these types of tasks.
“You were then dunked into the cold water in the dunker, you were not allowed to escape until you were tapped on the shoulder by a diver. It was a very long pause and you had to wait until your breath was about to run out and then escape.
“As a young, fit military pilot, I found that a very demanding task, but you could say that was the most realistic training I’d had.”
He said in the UK, the pool is reasonably warm, and you are given a thorough briefing before.
Having completed the same training that offshore workers received, Mr Prior said: “To have a reasonably warm pool is false, but if you are teaching people how to escape, you don’t want their first instinct to be to panic as they descend – so there’s a balance to strike between the realism of the training and the training itself.
“I believe if most people had to go through the French training, they would not choose to go offshore.”
Survivor Samuel Bull took his own life in London in 2017, which Sheriff Pyle said was “directly caused” by the crash.
The inquiry is being held virtually due to coronavirus measures.
A statement of agreed evidence read at the start of the inquiry confirmed that no mechanical fault was discovered with the helicopter, which was returning from the Borgsten Dolphin support vessel to Sumburgh Airport when it ditched.
The inquiry continues.
UK News
I've been using that accident regularly as an example of how not to use a 3-axis AP.
He said in the UK, the pool is reasonably warm, and you are given a thorough briefing before.
UK News
Originally Posted by [email protected]
I've been using that accident regularly as an example of how not to use a 3-axis AP.
or how not to use a 4-axis AP!
Join Date: Jan 2005
Location: Aberdeenshire.
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by [email protected]
Yes, absolutely
The AAIB reviewed the last 1000 ft of over 3000 onshore approaches where upper modes had been used. They found that less than 20% of these were flown with 4-axes engaged.
Last edited by marcr; 15th Sep 2020 at 22:31. Reason: Better description of data used and punctuation.
Join Date: Nov 1998
Location: UK
Posts: 460
Likes: 0
Received 0 Likes
on
0 Posts
It was common practice to fly the L2 in 3 axis as the IAS hold was quite poor. To fly 4 axis, you had to be very gentle with any speed changes or the aircraft would exchange altitude for speed. During a 200’ ARA this could be quite exciting. There’s no issue flying 3 axis as long as you monitor and apply power as the aircraft levels. Have I ever had to remind the PF to raise the lever in 3 axis...yes.
Join Date: Dec 2006
Location: UK and MALTA
Age: 61
Posts: 1,297
Likes: 0
Received 18 Likes
on
4 Posts
It was common practice to fly the L2 in 3 axis as the IAS hold was quite poor. To fly 4 axis, you had to be very gentle with any speed changes or the aircraft would exchange altitude for speed. During a 200’ ARA this could be quite exciting. There’s no issue flying 3 axis as long as you monitor and apply power as the aircraft levels. Have I ever had to remind the PF to raise the lever in 3 axis...yes.
If flying in 3 axis, with ALT hold engaged and the power setting is insufficient for level flight at Vy, the venerable AP will continue to raise the nose, speed decaying, to maintain the commanded altitude ([ALT]
If the power has been set low enough (paradoxically), the speed will decay through Vy. Now things get really exciting as the power demand for level flight increase exponentially as each knot of IAS is lost.
The AP keeps raising the nose in a departed effort to maintain the commanded ALT. Eventually a ROD will set in, now at low IAS, and if the crew do not intervene quickly enough and/or the surface is not far below the helicopter, a powered recovery may simply not be possible in time to prevent impact with the surface.
NOTE, the IAS and the ALT hold on the AS332 is more than competent. (as actually demonstrated by this accident). However, in 3 axis mode, power set below that required for level flight at Vy in any part of the envelope will result in a descent, required or otherwise.
This problem should be the No1 lesson for all 3 axis systems and 4 axis systems when operated in 3 axis.
As an aside, AIRBUS APM 2000 (EC225/175/145/135) incorporates flight envelope protections to "save" the crew/helicopter from these potentially disastrous mistakes.
This was not with ALT set, it was with VS engaged but the same concept applies.
You would expect a channel to disengage along with a warning with reducing IAS below a certain level (60 Kts for example) rather than stay engaged all the way to VRS.
You would expect a channel to disengage along with a warning with reducing IAS below a certain level (60 Kts for example) rather than stay engaged all the way to VRS.
Join Date: Dec 2006
Location: UK and MALTA
Age: 61
Posts: 1,297
Likes: 0
Received 18 Likes
on
4 Posts
Hi Crab, in the AS332L2, an engaged mode that cannot hold the selected parameter +minus a small value, will flash amber. No aural warning.
My understanding of this approach was the V/S was active to a preset ALT.A. So ALT would deploy at the set altitude. The previous stabilised approach during the descent then destabilised as there was no automatic or manual modulation of the power (collective).
As an aside, we spent many years teaching ourselves to reduce the IAS for an approach to minimums. Odd really when our FW brethren cant do that and have higher speeds and lower minimums than us. In 3 axis AP and modes its seems more prudent to mandate an approach speed at a minimum IAS of 100 KIAS. This provides some reaction time to modulate power etc. Flying a descent at Vy leaves little or no margin for correction if the IAS is allowed to tumble backwards with the PV curve working against the crew.
For 3 axis approach it is better to fly with IAS engaged for the descent as in order to maintain the glidepath the PF must routinely modify the collective setting which in turn keeps the control in his conscious mind at any level out for an MDH/A. This combined with a sensible IAS for the descent provides some protection albeit human rather than automatic.
My understanding of this approach was the V/S was active to a preset ALT.A. So ALT would deploy at the set altitude. The previous stabilised approach during the descent then destabilised as there was no automatic or manual modulation of the power (collective).
As an aside, we spent many years teaching ourselves to reduce the IAS for an approach to minimums. Odd really when our FW brethren cant do that and have higher speeds and lower minimums than us. In 3 axis AP and modes its seems more prudent to mandate an approach speed at a minimum IAS of 100 KIAS. This provides some reaction time to modulate power etc. Flying a descent at Vy leaves little or no margin for correction if the IAS is allowed to tumble backwards with the PV curve working against the crew.
For 3 axis approach it is better to fly with IAS engaged for the descent as in order to maintain the glidepath the PF must routinely modify the collective setting which in turn keeps the control in his conscious mind at any level out for an MDH/A. This combined with a sensible IAS for the descent provides some protection albeit human rather than automatic.
Agreed DB - on N3 and 412EP I have either flown with IAS coupled and manual collective or ILS/GS coupled just helping it with a small collective reduction at top of drop when the GS captures - all flown between 90 and 120 kts. Or just done it the old fashioned manual way
If I remember the accident report, they were already behind the drag curve of reducing IAS (not enough power applied) before they reached MDA (which is what they would presumably have had the ALTA set to)
If I remember the accident report, they were already behind the drag curve of reducing IAS (not enough power applied) before they reached MDA (which is what they would presumably have had the ALTA set to)
As an aside, we spent many years teaching ourselves to reduce the IAS for an approach to minimums. Odd really when our FW brethren cant do that and have higher speeds and lower minimums than us.
The faster you come down the slope the less time you have to cock it up; smaller groundspeed differences and less drift.
Last edited by Fareastdriver; 17th Sep 2020 at 19:48.
Join Date: Jan 2005
Location: Aberdeenshire.
Posts: 13
Likes: 0
Received 0 Likes
on
0 Posts
Whether or not you can, or indeed how you should, carry out a 3-axes approach is not the issue here.
The question remains - why would anybody CHOOSE, especially in marginal weather, to perform a 3-axes approach in a 4-axes capable aircraft? Or are we now advocating mixed mode flying?
If a similar coupled approach data set was analysed for the 225 we are unlikely to see even 2% of approaches flown 3-axes, let alone 82%.
So, is it the case, as Cyclic contends, that the L2 "IAS hold was quite poor" or is it reasonable to argue that, as DB puts it, "the IAS and the ALT hold on the AS332 is more than competent"?
The factual information gathered by the AAIB, and presented in their report, seems to support Cyclic's statement. Whether or not they were correct in doing so, for some reason, pilots were voting with their feet and electing to fly an approach in the L2 with only 3-axes coupled, the majority of the time.
This data was drawn from the operator's FDM records and that raises some further questions. If the clearly identifiable, mixed mode, 3-axes approaches were not neccessary, as the autopilot "was more than competent", then you might be forgiven for assuming that these events would be flagged to the training department for consideration and correction. On the other hand, if the evidence suggested that the "IAS hold was quite poor" you would perhaps expect to see some communication with the OEM to highlight the issue, and the associated feedback regarding the fault investigation and intended resolution.
However, if nothing was being done to address the perceived, or otherwise, problem with engaging a 4-axes coupled approach on the AS332L2 Super Puma, and pilots were being left to establish their own "work around" - then some might say, this was already "an accident waiting to happen".
Taking the quoted news headline,
"Helicopter would not have crashed if pilot had......"
I'll let you fill in the many blanks, which I'm sure will also be explained in detail to the inquiry.
The question remains - why would anybody CHOOSE, especially in marginal weather, to perform a 3-axes approach in a 4-axes capable aircraft? Or are we now advocating mixed mode flying?
If a similar coupled approach data set was analysed for the 225 we are unlikely to see even 2% of approaches flown 3-axes, let alone 82%.
So, is it the case, as Cyclic contends, that the L2 "IAS hold was quite poor" or is it reasonable to argue that, as DB puts it, "the IAS and the ALT hold on the AS332 is more than competent"?
The factual information gathered by the AAIB, and presented in their report, seems to support Cyclic's statement. Whether or not they were correct in doing so, for some reason, pilots were voting with their feet and electing to fly an approach in the L2 with only 3-axes coupled, the majority of the time.
This data was drawn from the operator's FDM records and that raises some further questions. If the clearly identifiable, mixed mode, 3-axes approaches were not neccessary, as the autopilot "was more than competent", then you might be forgiven for assuming that these events would be flagged to the training department for consideration and correction. On the other hand, if the evidence suggested that the "IAS hold was quite poor" you would perhaps expect to see some communication with the OEM to highlight the issue, and the associated feedback regarding the fault investigation and intended resolution.
However, if nothing was being done to address the perceived, or otherwise, problem with engaging a 4-axes coupled approach on the AS332L2 Super Puma, and pilots were being left to establish their own "work around" - then some might say, this was already "an accident waiting to happen".
Taking the quoted news headline,
"Helicopter would not have crashed if pilot had......"
I'll let you fill in the many blanks, which I'm sure will also be explained in detail to the inquiry.
Join Date: Dec 2006
Location: UK and MALTA
Age: 61
Posts: 1,297
Likes: 0
Received 18 Likes
on
4 Posts
Marcr, I cannot ever remember flying an IAP in 3 axis mode in the L2 except during training for degraded AFCS approaches. Prior to the EC225 it was the bestAP out there., L2 AP had no real disabilities when operated within its published AFM limitations. Certainly the IAS hold was competent as were all other modes.
Not wanting to go over old ground but the I remember that the general consensus at the time was had the helicopter been operated in 4 axis this accident would most likely not have happened. It was unusual approach. LOC ONLY. 09 to LSI. Maybe the mindset of the lack of G/S continued into the AFCS approach plan.
After this accident further tightening of industry policies for use of upper modes was widespread as it had started to be after the EC225 went into the sea on a night approach several years earlier. Hopefully, in this respect, crews are better informed and controlled by mandatory policies. Cue the old nutmeg “What about manual flying skills” well, we have to train hard to fight easy. All skills must be kept fresh......but just don’t do the degraded ones in IMC unless you have a real degrade.
Culture and common sense have to coincide.
Not wanting to go over old ground but the I remember that the general consensus at the time was had the helicopter been operated in 4 axis this accident would most likely not have happened. It was unusual approach. LOC ONLY. 09 to LSI. Maybe the mindset of the lack of G/S continued into the AFCS approach plan.
After this accident further tightening of industry policies for use of upper modes was widespread as it had started to be after the EC225 went into the sea on a night approach several years earlier. Hopefully, in this respect, crews are better informed and controlled by mandatory policies. Cue the old nutmeg “What about manual flying skills” well, we have to train hard to fight easy. All skills must be kept fresh......but just don’t do the degraded ones in IMC unless you have a real degrade.
Culture and common sense have to coincide.
From the summary of the accident report
Interestingly (just re-reading the report) They had identified an intermittent problem with the collective friction on climb out - it appeared to throw off a small amount of pitch after the lever was set at the desired Tq.
Second interesting point for DB - they did not arm the ALTA for the approach.
The commander was the Pilot Flying (PF) on the accident sector. The weather conditions were such that the final approach to Runway 09 at Sumburgh Airport was flown in cloud, requiring the approach to be made by sole reference to the helicopter’s instruments, in accordance with the Standard Operating Procedure (SOP) set out in the operator’s Operating Manual (OM). The approach was flown with the autopilot in 3-axes with Vertical Speed (V/S) mode, which required the commander to operate the collective pitch control manually to control the helicopter’s airspeed. The co-pilot was responsible for monitoring the helicopter’s vertical flightpath against the published approach vertical profile and for seeking the external visual references necessary to continue with the approach and landing. The procedures permitted the helicopter to descend to a height of 300 ft, the Minimum Descent Altitude (MDA) for the approach, at which point a level-off was required if visual references had not yet been acquired.
Although the approach vertical profile was maintained initially, insufficient collective pitch control input was applied by the commander to maintain the approach profile and the target approach airspeed of 80 kt. This resulted in insufficient engine power being provided and the helicopter’s airspeed reduced continuously during the final approach. Control of the flightpath was lost and the helicopter continued to descend below the MDA. During the latter stages of the approach the helicopter’s airspeed had decreased below 35 kt and a high rate of descent had developed.
Although the approach vertical profile was maintained initially, insufficient collective pitch control input was applied by the commander to maintain the approach profile and the target approach airspeed of 80 kt. This resulted in insufficient engine power being provided and the helicopter’s airspeed reduced continuously during the final approach. Control of the flightpath was lost and the helicopter continued to descend below the MDA. During the latter stages of the approach the helicopter’s airspeed had decreased below 35 kt and a high rate of descent had developed.
The investigation identified the following causal factors in the accident:
- The helicopter’s flight instruments were not monitored effectively during the latter stages of the non-precision instrument approach. This allowed the helicopter to enter a critically low energy state, from which recovery was not possible.
- Visual references had not been acquired by the Minimum Descent Altitude (MDA) and no effective action was taken to level the helicopter, as required by the operator’s procedure for an instrument approach.
- The operator’s SOP for this type of approach was not clearly defined and the pilots had not developed a shared, unambiguous understanding of how the approach was to be flown.
- The operator’s SOPs at the time did not optimise the use of the helicopter’s automated systems during a Non-Precision Approach.
- The decision to fly a 3-axes with V/S mode, decelerating approach in marginal weather conditions did not make optimum use of the helicopter’s automated systems and required closer monitoring of the instruments by the crew.
- Despite the poorer than forecast weather conditions at Sumburgh Airport, the commander had not altered his expectation of being able to land from a Non-Precision Approach.
Second interesting point for DB - they did not arm the ALTA for the approach.
