S-92 Loss of control event - report
Thread Starter
The standard O&G S-92 cannot be coupled below 55 KIAS (except Rad Alt on its own). With the SAR AFCS it can do a transition up from the hover.
Thread Starter
Most modern autopilots won't engage the mode unless it is inside parameters - if the GA mode specifies min IAS/TAS of 55 Kts then below that computer says Nooooo
Min IAS couple on the EC175 is 30kts, but it will engage GA in the hover. If no AP presets already made it will automatically select Vy and 1000ft/min RoC, otherwise it will use the presets. One of the reasons we don’t routinely use it from the hover is that if you are OEI below Vtoss (which in a 175 on the N Sea is always 40kts) it will prioritise getting to that Vtoss, which may result in a a rate of descent. However, it gets to Vtoss pretty quick so under the vast majority of N Sea conditions you would be unlikely to see much RoD if any. SOP is to engage GA at Vtoss.
Helpfully, if there is no lateral mode already coupled, then it will also roll wings level as well as accelerate and climb. It does that well enough and quickly enough to use as a Get Out Of Jail Free card in disorientation scenarios similar to that being discussed.
Helpfully, if there is no lateral mode already coupled, then it will also roll wings level as well as accelerate and climb. It does that well enough and quickly enough to use as a Get Out Of Jail Free card in disorientation scenarios similar to that being discussed.
Thread Starter
Helpfully, if there is no lateral mode already coupled, then it will also roll wings level as well as accelerate and climb. It does that well enough and quickly enough to use as a Get Out Of Jail Free card in disorientation scenarios similar to that being discussed.
Yes, AP RECOV. Double click on the AP engage button on the cyclic. In simple terms, it will recover the aircraft to straight and level. Both AP RECOV and GA seem to have similar reaction times, and work just fine, but GA will put you in a climb.
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Thread Starter
cheers, thanks for the update
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Somatographic illusion is rare in helo ops, but not unheard of. Particularly on high wind low visibility transitions to forward flight off offshore helidecks. The ‘feel’ of achieving Vtoss rapidly after departing the hover, sometimes with poor horizon but excellent lateral visual cues, coupled with the attitude pitch up from accelerative to speed stable attitude (on the S92 sometimes 15-20 deg pitch up) does catch one out from time to time. Not to say somaatogyral issues aren’t also
at play.
at play.
Thread Starter
Somatographic illusion is rare in helo ops, but not unheard of. Particularly on high wind low visibility transitions to forward flight off offshore helidecks. The ‘feel’ of achieving Vtoss rapidly after departing the hover, sometimes with poor horizon but excellent lateral visual cues, coupled with the attitude pitch up from accelerative to speed stable attitude (on the S92 sometimes 15-20 deg pitch up) does catch one out from time to time. Not to say somaatogyral issues aren’t also
at play.
at play.
If an aviation medicine expert wants to correct me, I'm happy to be so
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Min IAS couple on the EC175 is 30kts, but it will engage GA in the hover. If no AP presets already made it will automatically select Vy and 1000ft/min RoC, otherwise it will use the presets. One of the reasons we don’t routinely use it from the hover is that if you are OEI below Vtoss (which in a 175 on the N Sea is always 40kts) it will prioritise getting to that Vtoss, which may result in a a rate of descent. However, it gets to Vtoss pretty quick so under the vast majority of N Sea conditions you would be unlikely to see much RoD if any. SOP is to engage GA at Vtoss.
Helpfully, if there is no lateral mode already coupled, then it will also roll wings level as well as accelerate and climb. It does that well enough and quickly enough to use as a Get Out Of Jail Free card in disorientation scenarios similar to that being discussed.
Helpfully, if there is no lateral mode already coupled, then it will also roll wings level as well as accelerate and climb. It does that well enough and quickly enough to use as a Get Out Of Jail Free card in disorientation scenarios similar to that being discussed.
However time and time again we see that oil and gas accidents are caused by crew disorientation. Accidents are not caused by engine failures. And yet it seems there is still some prioritisation of engine failure risk over crew disorientation risk. Are they crazy?
Last edited by HeliComparator; 29th Feb 2024 at 14:17. Reason: they are crazy!
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It's the same with ab initio training, spending hours and hours doing engine failures, partial power loss, hydraulic failures etc
And when you look at the accident reports, most accidents are caused by pilots hitting things in perfectly servicable aircraft (the ground, fences, trees, etc)
the CAA are living in the dark ages
And when you look at the accident reports, most accidents are caused by pilots hitting things in perfectly servicable aircraft (the ground, fences, trees, etc)
the CAA are living in the dark ages
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I finally read this report, sounds like almost a carbon copy of the UH-60M incident in Mobile Bay several years back, although they narrowly avoided the same loss of life.
As non-rated crew, I’ve determined to:
(1. Not allow myself and my crew to depart in terrible weather conditions, make my concerns known.
(2. IF there’s an IIMC event, I’m bringing my scan inside to the PFD to cross monitor airspeed, rotor speed, attitude and positive rate of climb.
Just because I don’t have access to the controls doesn’t mean I can’t contribute.
As to my first point, I’m well aware that it’s easy to say what I’ll do when faced with pressure (real or self induced) to accomplish a flight, and there have been times where I SHOULD have said something but didn’t. Other times I DID say something, and it was well received by the crew and we delayed departure for better weather (or didn’t leave at all). I think verbalizing and even typing it down here helps reinforce the mindset though.
I have to say I’ve been blessed for the most part with crews that make it easy to make the right call. In my experience, the close calls with weather came from complacency, being with a crew that I had worked with for years, excessive professional courtesy kept me quiet a few times.
Other times, it was an unfamiliar crew mix and before I could even recognize it, rules were being “bent” to have “fun”. Both were sobering situations, ones I’d like to avoid going forward.
FltMech
As non-rated crew, I’ve determined to:
(1. Not allow myself and my crew to depart in terrible weather conditions, make my concerns known.
(2. IF there’s an IIMC event, I’m bringing my scan inside to the PFD to cross monitor airspeed, rotor speed, attitude and positive rate of climb.
Just because I don’t have access to the controls doesn’t mean I can’t contribute.
As to my first point, I’m well aware that it’s easy to say what I’ll do when faced with pressure (real or self induced) to accomplish a flight, and there have been times where I SHOULD have said something but didn’t. Other times I DID say something, and it was well received by the crew and we delayed departure for better weather (or didn’t leave at all). I think verbalizing and even typing it down here helps reinforce the mindset though.
I have to say I’ve been blessed for the most part with crews that make it easy to make the right call. In my experience, the close calls with weather came from complacency, being with a crew that I had worked with for years, excessive professional courtesy kept me quiet a few times.
Other times, it was an unfamiliar crew mix and before I could even recognize it, rules were being “bent” to have “fun”. Both were sobering situations, ones I’d like to avoid going forward.
FltMech
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From a pre-World War II pilot.....He might have added....the one you do not train for kills you.
