Question for the offshore experts
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Question for the offshore experts
EHEST (European Helicopter Safety Team) have published an excellent and thought-provoking document called 'Automation and Flight Path Management'. It begins with an example of how autopilot mismanagement can lead to near disaster. It involved an unknown helicopter type in what I assume was a night take off from an offshore platform in what was clearly night IMC.
I did my annual CRM refresher this week and the topic for discussion was the AW139 crash in Norfolk. This also involved a night IMC take off attempt which we know ended in disaster. One issue discussed was the Flight Manual requirement to have an IAS of at least 50 knots before entering IMC (Vmini = 50kts).
This rather begs the question how is it possible to operate offshore at night when many departures pitch you into instant blackness (in pouring rain?) the second you leave the glare of the platform lighting. After all these years this is the first time this anomaly has occurred to me. How do we square this particular circle?
G
I did my annual CRM refresher this week and the topic for discussion was the AW139 crash in Norfolk. This also involved a night IMC take off attempt which we know ended in disaster. One issue discussed was the Flight Manual requirement to have an IAS of at least 50 knots before entering IMC (Vmini = 50kts).
This rather begs the question how is it possible to operate offshore at night when many departures pitch you into instant blackness (in pouring rain?) the second you leave the glare of the platform lighting. After all these years this is the first time this anomaly has occurred to me. How do we square this particular circle?
G
I think the key point is that the departure is a dynamic situation with an acceleration through Vmini, whereas the original requirements for Vmini revolve around longitudinal stability in trimmed flight. AC29 already makes provision for speeds below Vmini in the approach phase.
There doesn't seem to me to be any practical difference between being IMC or being in the pitch dark with zero visual reference. So the point is on a "legal technicality" rather than anything practical. As 212 say the important thing is to maintain the appropriate accelerative attitude and in the case of something like the 225, engage GA as soon as there is positive airspeed showing.
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If you are not in sight of the surface ( pitch black over the oggin), then you are by definition IMC! They have to be careful writing the RFM too proscriptively, otherwise they effectively make OGP work illegal at night!
I think the key point is that the departure is a dynamic situation with an acceleration through Vmini, whereas the original requirements for Vmini revolve around longitudinal stability in trimmed flight. AC29 already makes provision for speeds below Vmini in the approach phase.
And this is a departure not an approach.
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When is IMC ...... well...... IMC??
Looks like there is a rock to be rolled over here. Our man in Norfolk did something many condemn as foolish even illegal but certainly his departure was in IMC by any definition of those conditions but what, in essence, was different from the guy in the EHEST booklet?
Both took off at night, both were unable to ensure that the take off could be completed using external references until a safe Vmini could be achieved.
We condemn one and choose to 'tolerate' the other. Do we have our house in order? When disaster strikes the lawyers have a field day. Shouldn't things be a little less 'wooly' for all our sakes. If the overall verdict on the Norfolk crash is one that comes out against departures without visual reference we could see pilot's representatives or those who represent offshore workers offering advice to avoid take offs offshore at night where there is insufficient visual reference in case they have an accident or incident.
G.
Both took off at night, both were unable to ensure that the take off could be completed using external references until a safe Vmini could be achieved.
We condemn one and choose to 'tolerate' the other. Do we have our house in order? When disaster strikes the lawyers have a field day. Shouldn't things be a little less 'wooly' for all our sakes. If the overall verdict on the Norfolk crash is one that comes out against departures without visual reference we could see pilot's representatives or those who represent offshore workers offering advice to avoid take offs offshore at night where there is insufficient visual reference in case they have an accident or incident.
G.
Neither of these events were a consequence of being below Vmini and in fact developed once above it, so I think it's a red herring. It was a concept drawn up long before tripple redundant digital AFCSs so the only valid argument I would see is that it should no longer be a limitation. Just to further muddy things, if you read Part 29/AC-29 you will see it's minimum IFR speed so in those countries with night VFR it is irrelevant as a limitation!
with night VFR it is irrelevant as a limitation
Depends which state of course! On the subject of being able to see the surface, I suspect it is normal to have some sight of the surface when the lights are pointing down at it, but whether that gives any useful reference, especially if it's calm, is another matter.
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A solution at hand?
I guess we will soon see the arrival of multiple FCOM's and I'm sure these grey areas will be addressed. I'm also sure that with so much expertise to hand they will do so in such a way that reinforces the OEM's view on the average piloting skills available to deal with those real but uncommon situations where the ability to maintain sufficient surface contact and useful (?) forward visibility overtake the unsuspecting offshore aviator.
What we don't want, of course, is for the OEM to come to the opinion that the night environment is universally benign or universally impossible. Thank goodness that OEM's have at their disposal copious numbers of offshore experienced pilots that thoroughly understand the feeling you get when you pitch ten degrees nose down on a dark, moonless rainy night and the overwhelming desire to keep looking outside is overcome by the need to get on the dials as you accelerate through the flicker of 20 knots and stare at the VSI daring it to read less than zero.
G.
What we don't want, of course, is for the OEM to come to the opinion that the night environment is universally benign or universally impossible. Thank goodness that OEM's have at their disposal copious numbers of offshore experienced pilots that thoroughly understand the feeling you get when you pitch ten degrees nose down on a dark, moonless rainy night and the overwhelming desire to keep looking outside is overcome by the need to get on the dials as you accelerate through the flicker of 20 knots and stare at the VSI daring it to read less than zero.
G.
it should no longer be a limitation.
In the Norfolk crash, the impact may have happened above Vmini but the actions that caused that crash were initiated below it and that is the whole issue.
We all know you can fly/hover a helicopter on instruments below Vmini - providing you have been trained (and tested) to ensure you can do it safely.
Originally Posted by [email protected]
In the Norfolk crash, the impact may have happened above Vmini but the actions that caused that crash were initiated below it and that is the whole issue.
Yes, but why????
Because Vmini is a limitation (whether it should be or not is a matter for discussion), they had not been trained to fly below it nor been tested in their ability to fly below it on their IR or any subsequent checks.
When they tried it, they screwed it up because they weren't looking in the right place (AI) for the information they needed to safely conduct the transition.
Therefore, the Vmini is not a red herring.
It seems to be regarded by the manufacturers and the regulators as illegal yet the offshore community do it as a matter of course for night rig departures.
Isn't that what Geoffers was referring to about squaring the circle? It is widely done yet not within the rules so something of a catch 22.
Because Vmini is a limitation (whether it should be or not is a matter for discussion), they had not been trained to fly below it nor been tested in their ability to fly below it on their IR or any subsequent checks.
When they tried it, they screwed it up because they weren't looking in the right place (AI) for the information they needed to safely conduct the transition.
Therefore, the Vmini is not a red herring.
It seems to be regarded by the manufacturers and the regulators as illegal yet the offshore community do it as a matter of course for night rig departures.
Isn't that what Geoffers was referring to about squaring the circle? It is widely done yet not within the rules so something of a catch 22.
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That EHEST guide is here: HE9 Automation and Flight Path Management
Same again - really??
Night DLs are very similar to rig departures and I have done quite a few of those.
I don't claim to be an offshore expert but I do have lots of pertinent experience.
Night DLs are very similar to rig departures and I have done quite a few of those.
I don't claim to be an offshore expert but I do have lots of pertinent experience.
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All with relevant experience welcome...
... and the educated ex-mil world may well offer a fresh view on the matter.
and another thing.....
The EHEST document has the flavour of one of the 'old hands' talking as it refers to the notion that it's a good idea to enter a turn by pushing against the trim motor springs because an unusual attitude can be recovered by simply letting go of the cyclic.
I hope this is not taken seriously. In the AW139 you should trim into a turn. This is just what the AP does when a turn is commanded during 'auto' flight. If you have an AP failure in an AW139, for example, it's likely to occur because some wise guy has disguised the AP OFF button on the cyclic by calling it the 'SAS RELEASE' consequently it is often confused with the (nearby) button called 'FD SBY'. One single push of the SAS REL button removes both the AP's in one fell swoop. Statistically this is the single most common way that AP OUT flight mode is entered during my recurrent training sessions in the sim.
As a general rule you need (IMHO) a recovery strategy for unusual attitudes that deals with all eventualities given than you wouldn't have much time to play around if the aircraft is threatening to treat you to a touch of inverted flight. Best not to rely on the AP to play a part in your strategy so please ignore those that invite you to push against the springs or for that matter to use the GA mode to help.(RFM suggests it has a use in this respect - not very smart though).
You may have only a few seconds to get it right so stick to the tried and trusted method, wings level, balance, pitch - nose on the horizon then as required by the IAS, power as required when pitch is sorted.
I wonder if EHEST could publish a correction? I guess an SFI who's been doing this stuff for more than 3000 hours may not have quite the clout required but you never know.
G.
and another thing.....
The EHEST document has the flavour of one of the 'old hands' talking as it refers to the notion that it's a good idea to enter a turn by pushing against the trim motor springs because an unusual attitude can be recovered by simply letting go of the cyclic.
I hope this is not taken seriously. In the AW139 you should trim into a turn. This is just what the AP does when a turn is commanded during 'auto' flight. If you have an AP failure in an AW139, for example, it's likely to occur because some wise guy has disguised the AP OFF button on the cyclic by calling it the 'SAS RELEASE' consequently it is often confused with the (nearby) button called 'FD SBY'. One single push of the SAS REL button removes both the AP's in one fell swoop. Statistically this is the single most common way that AP OUT flight mode is entered during my recurrent training sessions in the sim.
As a general rule you need (IMHO) a recovery strategy for unusual attitudes that deals with all eventualities given than you wouldn't have much time to play around if the aircraft is threatening to treat you to a touch of inverted flight. Best not to rely on the AP to play a part in your strategy so please ignore those that invite you to push against the springs or for that matter to use the GA mode to help.(RFM suggests it has a use in this respect - not very smart though).
You may have only a few seconds to get it right so stick to the tried and trusted method, wings level, balance, pitch - nose on the horizon then as required by the IAS, power as required when pitch is sorted.
I wonder if EHEST could publish a correction? I guess an SFI who's been doing this stuff for more than 3000 hours may not have quite the clout required but you never know.
G.
Last edited by Geoffersincornwall; 12th Dec 2015 at 18:18. Reason: clarification
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Again and again
Geoff,
Some old stuff here. In the 365 series, I always operated and advocated the night/IFR takeoff to be initiated from the get-go hard on the instruments. The old ITO if you may.
I always placed the heading bug on the expected initial turn to heading and activated the heading hold after take off and normal climb attitude was attained plus known obstacle clearance altitude reached.
This worked well for me for many years. But when *** took over SAW, their training department shot me down with vengeance. Their stance was to have the heading bug on the take off heading and activate the heading hold as soon as airspeed allowed then let "George" manage things.
In my opinion, a pilot who is solid on the scan from initial power application through climb to cruise flight attitude is less likely to lose situational awareness than one who uses automation so early on in the take off run.
Cheers,
Gray
Some old stuff here. In the 365 series, I always operated and advocated the night/IFR takeoff to be initiated from the get-go hard on the instruments. The old ITO if you may.
I always placed the heading bug on the expected initial turn to heading and activated the heading hold after take off and normal climb attitude was attained plus known obstacle clearance altitude reached.
This worked well for me for many years. But when *** took over SAW, their training department shot me down with vengeance. Their stance was to have the heading bug on the take off heading and activate the heading hold as soon as airspeed allowed then let "George" manage things.
In my opinion, a pilot who is solid on the scan from initial power application through climb to cruise flight attitude is less likely to lose situational awareness than one who uses automation so early on in the take off run.
Cheers,
Gray
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It's always a problem when the discussion is about the latest generation of helicopters for they appear to have some divergent design characteristics. Airbus use one philosophy and AW another and from what I understand Sikorsky is somewhere in between. Bell may well have another when we get to know the '555' a little better.
Comparing them with previous generations is where we run into problems for those brought up on those machines will find it difficult to take on board the news that you must change your technique as well as your prejudices about how to interact with automation.
The AW139 is designed to be flown using maximum automation. It is capable of single pilot operation so this has influenced the designers. Airbus, I believe, has a very sophisticated autopilot and so should also be operated in a way that makes most use of the automation.
To apply the techniques of the previous generation of helicopters to the current one is not recommended so I would tend to favour the early use of automation during the departure but the key here is that the example used by EHEST resulted in a near miss because automation was used incorrectly. Had the crew received proper training then they would have understood this.The reality is that a night offshore take off is a high risk event requiring the pilot to use maximum skill to achieve a safe departure. On a moonlit night you wonder what the fuss is about but when the opposite is the case we are forced by custom and practice to treat it as routine.
These days we have at last admitted that it was a bad idea to fly around over a Sea State 6 with floatation equipment certified for Sea State 4. Will we one day have a night operating limit that takes account of the Vmini limitation and restricts such flights to genuine night VMC?
G.
Comparing them with previous generations is where we run into problems for those brought up on those machines will find it difficult to take on board the news that you must change your technique as well as your prejudices about how to interact with automation.
The AW139 is designed to be flown using maximum automation. It is capable of single pilot operation so this has influenced the designers. Airbus, I believe, has a very sophisticated autopilot and so should also be operated in a way that makes most use of the automation.
To apply the techniques of the previous generation of helicopters to the current one is not recommended so I would tend to favour the early use of automation during the departure but the key here is that the example used by EHEST resulted in a near miss because automation was used incorrectly. Had the crew received proper training then they would have understood this.The reality is that a night offshore take off is a high risk event requiring the pilot to use maximum skill to achieve a safe departure. On a moonlit night you wonder what the fuss is about but when the opposite is the case we are forced by custom and practice to treat it as routine.
These days we have at last admitted that it was a bad idea to fly around over a Sea State 6 with floatation equipment certified for Sea State 4. Will we one day have a night operating limit that takes account of the Vmini limitation and restricts such flights to genuine night VMC?
G.
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There is a lot of tricky legal speak going on and in some cases the RFM’s do not help the cause. As we all know, lawyers these days will have an input in the design and construction of procedures and manuals, so that in the event of something going wrong the blame can be mitigated.
The solution from the operators side lies squarely in the training departments and thorough, detailed, standardized techniques to as far as possible alleviate the risks during a night departure. I would not say VMini is a red herring, but TDP during the departure is the more relevant and the setup immediately after TDP as well as performance characteristics at any given departure. The move toward P2E is step in the right direction, and should effectively remove exposure time. Therefore as long as one is visual at TDP, which is a height reference over the deck, the key is to accurately achieve the correct attitude at this point. This needs to be a “climbing, accelerative attitude”. The single biggest flaw in technique I witness during night takeoffs is when pilots are too dynamic with the nose forward attitude, resulting in degrees of over-controlling and often in purely accelerative attitude with little or no climb initially and quite often a descent. The lack of aerodynamic understanding and especially with reference to the non-linear properties of drag effects, has, IMO led to a belief that it is important to slavishly attain speed as an ultimate priority during departure. In so doing one has a greater power demand during the higher pitch forward attitude and further increase in the possibility of disorientation and further over controlling. Trying to get pilots to understand the value of smooth control inputs during departure is the greatest challenge.
Assuming one has visual references (rig/deck) up until TDP and P2E, at TDP one has to “smoothly" set the climb/accel attitude with minimum additional control input, toward VTOSS/VY. Up to TDP (height) any failure has the required visual references to ensure a rejected takeoff. With P2E ensured there should in theory be no requirement for visual references as a water landing is not a calculated performance risk in the event of power loss. Yes we all know an engine failure is not he only failure, however during a departure it is the greatest risk of a resultant ditching from a purely technical standpoint. Therefore immediately after TDP pilots must already be in the correct flight attitude to maintain the climb and acceleration toward Vmini/VToss.
Perhaps its is wording of certain RFM’s that should be adjusted, but I am also of the opinion that during a dynamic phase of flight such as departure, the time spent below VMini is at an absolute minimum and the aircraft, at the time of IMC is set up in a configuration to achieve this in a very short space of time and hence in the case of an ITO should not be interpreted as prohibitive assuming correct techniques are in use.
The solution from the operators side lies squarely in the training departments and thorough, detailed, standardized techniques to as far as possible alleviate the risks during a night departure. I would not say VMini is a red herring, but TDP during the departure is the more relevant and the setup immediately after TDP as well as performance characteristics at any given departure. The move toward P2E is step in the right direction, and should effectively remove exposure time. Therefore as long as one is visual at TDP, which is a height reference over the deck, the key is to accurately achieve the correct attitude at this point. This needs to be a “climbing, accelerative attitude”. The single biggest flaw in technique I witness during night takeoffs is when pilots are too dynamic with the nose forward attitude, resulting in degrees of over-controlling and often in purely accelerative attitude with little or no climb initially and quite often a descent. The lack of aerodynamic understanding and especially with reference to the non-linear properties of drag effects, has, IMO led to a belief that it is important to slavishly attain speed as an ultimate priority during departure. In so doing one has a greater power demand during the higher pitch forward attitude and further increase in the possibility of disorientation and further over controlling. Trying to get pilots to understand the value of smooth control inputs during departure is the greatest challenge.
Assuming one has visual references (rig/deck) up until TDP and P2E, at TDP one has to “smoothly" set the climb/accel attitude with minimum additional control input, toward VTOSS/VY. Up to TDP (height) any failure has the required visual references to ensure a rejected takeoff. With P2E ensured there should in theory be no requirement for visual references as a water landing is not a calculated performance risk in the event of power loss. Yes we all know an engine failure is not he only failure, however during a departure it is the greatest risk of a resultant ditching from a purely technical standpoint. Therefore immediately after TDP pilots must already be in the correct flight attitude to maintain the climb and acceleration toward Vmini/VToss.
Perhaps its is wording of certain RFM’s that should be adjusted, but I am also of the opinion that during a dynamic phase of flight such as departure, the time spent below VMini is at an absolute minimum and the aircraft, at the time of IMC is set up in a configuration to achieve this in a very short space of time and hence in the case of an ITO should not be interpreted as prohibitive assuming correct techniques are in use.