AW139 G-LBAL helicopter crash in Gillingham, Norfolk
I suspect the conditions were pretty much as safe as they are for a dark rig departure with no visual references - when, as has been discussed before, the crew climb vertically on instruments before pitching down to generate translation lift to achieve VMini and climb away
By far the best way of doing so is to achieve VMini+ in VMC then climb into IMC on instruments at VMini+ to MSA
Last edited by 212man; 19th Oct 2015 at 14:09.
Avoid imitations
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Rotorspeed, from what I've read so far, 800 metres visibility is likely to be required for Part NCC operations.
I haven't seen a minimum cloud base laid down under those new regulations. But it makes sense for it to be high enough for a Class 1 departure profile to be flown as far as the increase in IAS to Vy to be achieved in VMC.
There may be some regularly used private sites in UK where a Vmini climb needs to be held for a protracted period but I haven't experienced them. I would always aim to climb at Vy iaw the profile being flown. For PT operations this would be mandatory anyway. Although flying in a private capacity, I always aim to fly to Class 1.
I haven't seen a minimum cloud base laid down under those new regulations. But it makes sense for it to be high enough for a Class 1 departure profile to be flown as far as the increase in IAS to Vy to be achieved in VMC.
There may be some regularly used private sites in UK where a Vmini climb needs to be held for a protracted period but I haven't experienced them. I would always aim to climb at Vy iaw the profile being flown. For PT operations this would be mandatory anyway. Although flying in a private capacity, I always aim to fly to Class 1.
212man - what visual references are you using in the dark from a rig? If you are very lucky you might have enough starlight and moonlight to have the glimmer of a horizon but more often than not you won't.
If you are using the AI/AH/PFD for assessing the aircraft attitude, you are flying on instruments (below Vmini) not flying visually.
If you are using the rig as a visual reference in the vertical climb until rotation point, you are still transferring to instruments below Vmini after that point.
If you are using the AI/AH/PFD for assessing the aircraft attitude, you are flying on instruments (below Vmini) not flying visually.
If you are using the rig as a visual reference in the vertical climb until rotation point, you are still transferring to instruments below Vmini after that point.
How far is it from the parked position offshore to the Rotation point on a Night Offshore Takeoff with no visible surface reference other than the Deck and Rig?
Memory serves me the purely vertical ascent ends where the Rotation begins and usually is at the Deck Edge so there is not much Visibility required on that long transit from the Parking location to the Deck Edge unless the high price of Petrol I have had to pay has facilitated much larger decks offshore these days.
Memory serves me the purely vertical ascent ends where the Rotation begins and usually is at the Deck Edge so there is not much Visibility required on that long transit from the Parking location to the Deck Edge unless the high price of Petrol I have had to pay has facilitated much larger decks offshore these days.
212man - what visual references are you using in the dark from a rig? If you are very lucky you might have enough starlight and moonlight to have the glimmer of a horizon but more often than not you won't.
I was merely countering this comment:
the crew climb vertically on instruments before pitching down
In the context of this accident, we also had standard calls for unusual attitudes developing, low airspeed, high rates of descent etc and would brief their importance before departure.
....high price of Petrol I have had to pay
212man - pretty much what I thought and the same I would use departing from the back of a frigate or other grey-funnel liner.
There is therefore a disconnect between what is done in the real world and what is required for an IR - other posters have pointed out that flight below Vmini is not covered on the rating or the training for that rating.
Are you complying with the RFM if you are flying with reference to the instruments below Vmini?
Personally I think it is fine - it is part of the transition from hover to forward flight that makes helicopters so useful - but there are plenty of pedants who would never condone IF flight below Vmini in any circumstances.
There is therefore a disconnect between what is done in the real world and what is required for an IR - other posters have pointed out that flight below Vmini is not covered on the rating or the training for that rating.
Are you complying with the RFM if you are flying with reference to the instruments below Vmini?
Personally I think it is fine - it is part of the transition from hover to forward flight that makes helicopters so useful - but there are plenty of pedants who would never condone IF flight below Vmini in any circumstances.
Are you complying with the RFM if you are flying with reference to the instruments below Vmini
Someone like John Dixon, Shawn Coyle etc can give a more definitive answer.
212man - I am sure you are right about stability and workload but the Vmini must also have something to do with the reliability and accuracy of the pressure instruments since few pitot systems are calibrated below 30KIAS.
The question then becomes - what are you using to assess the aircraft's speed between leaving the hover (assuming nil wind) and Vmini? Doppler/GPS/INS?
Is anyone trained to use that or assessed on that process for an IR???
It all seems something of a grey area that the regulators have turned a blind eye to.
The question then becomes - what are you using to assess the aircraft's speed between leaving the hover (assuming nil wind) and Vmini? Doppler/GPS/INS?
Is anyone trained to use that or assessed on that process for an IR???
It all seems something of a grey area that the regulators have turned a blind eye to.
I think it's given as read that the Vmini will be based on an accurate IAS. Below that speed, there may be an accurate IAS available but stability issues.
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Quite agree Vy usually most sensible climb speed but it could just be on some types that Vy is less than VMini - which is why I said VMini+, with IMC being focal issue. Sorry wasn't very clear and too abreviated perhaps! You could argue VTOSS would be safest climb speed for IMC obstacle avoidance clearance being nearest to Vx (best angle), but that is almost always less that VMini.
Quite agree Vy usually most sensible climb speed but it could just be on some types that Vy is less than VMini - which is why I said VMini+, with IMC being focal issue. Sorry wasn't very clear and too abreviated perhaps! You could argue VTOSS would be safest climb speed for IMC obstacle avoidance clearance being nearest to Vx (best angle), but that is almost always less that VMini.
212man - I don't know about your AP but mine in ATT mode (normal selection) copes very well with flapback, inflow roll and tuckunder in the transition from the hover.
My point is that you could have a lower Vmini if the pitot system was good enough but none seem to be. It is easily possible to control the aircraft on instruments below Vmini but it won't be certified that way because of the inaccuracies of the pitot system.
My point is that you could have a lower Vmini if the pitot system was good enough but none seem to be. It is easily possible to control the aircraft on instruments below Vmini but it won't be certified that way because of the inaccuracies of the pitot system.
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Vmini higher than Vy?
I'd be surprised if this was allowable for any IFR certificated aircraft! If it was allowed, how could you carry out a legal go around in IMC?
VTOSS is achieved quite rapidly following rotation (8 seconds in nil wind?). After that a climb attitude has to be set to avoid an excessive acceleration in IAS at the expense of rate of climb. In the AW139 this attitude results in a controlled acceleration to a speed a little above Vy. Vmini is also reached moments after VTOSS and the AFCS can be engaged. Or not. Personally, I would let the aircraft continue to accelerate and climb if it is already doing just that. A misaction during this critical phase could upset a running system.
The moment the aircraft left the ground (which was a bad decision), it was committed to the take-off. If the aircraft had the power for an OGE climb (which it had to), there was no real need to rotate at a low height (another bad decision). The cockpit had two people in it but it didn’t make the situation safer, as the crew did not know how to work together to decide upon and execute a safe course of action. Which in this case, would have been to say NO.
Great discussion. Chewing over what is and isn’t legal is important. No less the importance of doing things sensibly when having to make decisions in the grey zones and the law or employer culture can’t give the right answer.
The moment the aircraft left the ground (which was a bad decision), it was committed to the take-off. If the aircraft had the power for an OGE climb (which it had to), there was no real need to rotate at a low height (another bad decision). The cockpit had two people in it but it didn’t make the situation safer, as the crew did not know how to work together to decide upon and execute a safe course of action. Which in this case, would have been to say NO.
Great discussion. Chewing over what is and isn’t legal is important. No less the importance of doing things sensibly when having to make decisions in the grey zones and the law or employer culture can’t give the right answer.
As a practical rider to the above, the normal rotation profile could have beeen amended to simply putting the nose on the horizon, with no nose-down attitude. VTOSS would have been gained whilst continuing to climb and with a lesser risk of illusions or fixation. At the height where they rotated, there was no need for a rapid acceleration.
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Training??? Licensing????
As I was reminded recently at a Training Conference every accident report almost always begins
"The pilot was properly licensed, the pilot was properly qualified, he/she had x thousand hours of experience."
What does that say about our licensing system and the training that supports it?
G.
"The pilot was properly licensed, the pilot was properly qualified, he/she had x thousand hours of experience."
What does that say about our licensing system and the training that supports it?
G.
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I don't know it says anything about our licensing or training - it just shows that even trained, qualified and experienced people make mistakes.
But this was a big mistake, fundamental to safely flying the helicopter, not a missed RT call or an incorrect altimeter setting.
Torquetalk - I presume when you say 'the AFCS can be engaged' you mean the upper or autopilot modes can be engaged (ALTA, TAS hold etc) once above Vmini. The AFCS should be providing at least rate damping (SAS) but more likely Attitude hold in the hover and during the transition.
Geoffers - I agree - does the licensing process not look more like a box-ticking exercise rather than an assessment of flying ability?
Torquetalk - I presume when you say 'the AFCS can be engaged' you mean the upper or autopilot modes can be engaged (ALTA, TAS hold etc) once above Vmini. The AFCS should be providing at least rate damping (SAS) but more likely Attitude hold in the hover and during the transition.
Geoffers - I agree - does the licensing process not look more like a box-ticking exercise rather than an assessment of flying ability?
Yes crab, I mean exactly that. No need to be risking finger trouble by selecting autopilot cues at a critical phase of flight when things are going nicely. Better wait until the aircraft has reached a safe height and attained Vy or better. I think when to be selecting higher modes is also situation dependent. If it is a programmed SID, you may well want to select NAV at Vmini, especially if going IMC at a very ealry stage.
Licensing focuses on certain flying standard, but these rarely have any bearing on accident situations. That's why we have CRM and why it is important for multi-crew and especially important for pilots operating alone.
I find some of the simplest situations begin to get loaded if CRM and MCC are poor, whereas more complicated situations are managed comfortably by a crew that knows what it is doing and communicates well.
TT
Licensing focuses on certain flying standard, but these rarely have any bearing on accident situations. That's why we have CRM and why it is important for multi-crew and especially important for pilots operating alone.
I find some of the simplest situations begin to get loaded if CRM and MCC are poor, whereas more complicated situations are managed comfortably by a crew that knows what it is doing and communicates well.
TT
A question that I see about CRM as it relates to the reality of the Cockpit can be summed by asking......"How effective is the transfer of knowledge gained during CRM Training conveyed into Operator Procedures, SOP's, and Cockpit Crew Coordination/Function?
All the CRM training in the world does not have much benefit if the principles learned are not translated into effective implementation by the Operator/Crew.
Do we actually confirm at the individual level we have fully incorporated CRM teachings to the necessary level that would prevent these kinds of Tragedies from happening?
All the CRM training in the world does not have much benefit if the principles learned are not translated into effective implementation by the Operator/Crew.
Do we actually confirm at the individual level we have fully incorporated CRM teachings to the necessary level that would prevent these kinds of Tragedies from happening?