I thought it was probably a vortex ring state, they have not given that as the cause yet, but if the aircraft was still descending with the pilot pulling in power, that would explain it.
http://www.bbc.co.uk/news/uk-scotland-n ... d-24586824
tut
Pilot error
Re: Pilot error
Was going to find the thread, but looks like you were on the money.
Emira - Volvo spec
A1 Black Edition - Ilford HP5 spec
A1 Black Edition - Ilford HP5 spec
Re: Pilot error
unpalatable as it may be, this one does look like plain crew failure, several key events not acted upon until all too late (reading the AAIB report).tut wrote:I thought it was probably a vortex ring state, they have not given that as the cause yet, but if the aircraft was still descending with the pilot pulling in power, that would explain it.
http://www.bbc.co.uk/news/uk-scotland-n ... d-24586824
tut
Re: Pilot error
Thought so at the time so they have now confirmed it, pity that it takes so long.tut wrote:Critical points, 240' below the correct flight path, speed decreased below 30kts, close to ground contact, collective pulled up to increase power, helicopter goes into Vortex ring state which means it is virtually falling through a vacuum, full power but no way out.
This is just my opinion from the evidence released, but not necessarily correct, just based on experience.
tut
tut
Re: Pilot error
And what causes that Tut? A natural phenomena caused by a combination of weather and location?
VX220 SC
M135i
Parajet V3 Moster 185
M135i
Parajet V3 Moster 185
Re: Pilot error
Nope, happens virtually every time that a helicopter gets into that configuration. Helicopters in commercial operations take off using a runway so that they reach a forward airspeed of 35 kts before rotating into a climb. At this stage only partial power is used as forward speed gives lift. When lifting off from an oil platform with a full load, max power is used as it has to lift vertically and that continues into forward flight until speed overcomes lift. This is why it is such a crucial stage if you have an engine failure.
On the CHC flight they decreased speed from 80kts, through 70, and finally 35 whilst descending at 1,000' fpm. When the pilot realised that they were going to crash he applied full power and got into a vortex ring state, which is a very dangerous condition that surrounds the rotor causing severe loss of lift. Essentially, the helicopter descends into its own downwash. When that happens, increasing the rotor power merely feeds the vortex state without generating additional lift. The only way out is to decrease power, stick the nose down to get out of the ring, and gain speed.
However he was too late and too low to be able to do that.
tut
ps:- very difficult to understand how an experienced crew could get into that configuration, they had ample warning, the autopilot was warning them and also trying to correct for their errors, but they continued to bring back the speed way before the actual landing. The only time that I have been in VR is during training when it was deliberately induced to demonstrate what would happen if you got into it. I flew single pilot much of the time, listening to NorthSound and finishing my lunch on the approach, but still could not manage it.
pss:- on the other hand I don't think I told the story of when I flew straight over the top of Aberdeen Airport sound asleep, and did not wake up until part way to Perth.
On the CHC flight they decreased speed from 80kts, through 70, and finally 35 whilst descending at 1,000' fpm. When the pilot realised that they were going to crash he applied full power and got into a vortex ring state, which is a very dangerous condition that surrounds the rotor causing severe loss of lift. Essentially, the helicopter descends into its own downwash. When that happens, increasing the rotor power merely feeds the vortex state without generating additional lift. The only way out is to decrease power, stick the nose down to get out of the ring, and gain speed.
However he was too late and too low to be able to do that.
tut
ps:- very difficult to understand how an experienced crew could get into that configuration, they had ample warning, the autopilot was warning them and also trying to correct for their errors, but they continued to bring back the speed way before the actual landing. The only time that I have been in VR is during training when it was deliberately induced to demonstrate what would happen if you got into it. I flew single pilot much of the time, listening to NorthSound and finishing my lunch on the approach, but still could not manage it.
pss:- on the other hand I don't think I told the story of when I flew straight over the top of Aberdeen Airport sound asleep, and did not wake up until part way to Perth.
Re: Pilot error
I would never believe this if it wasn't you!tut wrote:pss:- on the other hand I don't think I told the story of when I flew straight over the top of Aberdeen Airport sound asleep, and did not wake up until part way to Perth.
Exige GT
Re: Pilot error
tut wrote:pss:- on the other hand I don't think I told the story of when I flew straight over the top of Aberdeen Airport sound asleep, and did not wake up until part way to Perth.
Did you wear shoes/boots when you were flying at that time Tut?
Steve.
Re: Pilot error
Falling asleep in flight happened several times with crews, mostly two pilot ones, so mine was only half a cock up. With fixed wing flights it is almost common place.
In my case it was the end of a nine hour flying day in August finishing off with a four hour freight flight back from the Magnus into a headwind. Three in the afternoon flying into the sun, no A/C and the windows do not open, so like a sauna. 2,500ft, we did not have auto pilot in the S76 but you could trim it out into level flight, not sure when I nodded off but it was before Peterhead. What saved me from demotion, probably would not have been sacked being single pilot, was a Summer storm, and lightning knocked out the airports radar. Standard procedure when this happens is to overfly the airport on the same heading and altitude which ensures separation until it is sorted out. I think the thunder woke me up, by which time they were recalling the aircraft in turn for landing.
Sometimes you take the elevator, sometimes you take the shaft........
tut
In my case it was the end of a nine hour flying day in August finishing off with a four hour freight flight back from the Magnus into a headwind. Three in the afternoon flying into the sun, no A/C and the windows do not open, so like a sauna. 2,500ft, we did not have auto pilot in the S76 but you could trim it out into level flight, not sure when I nodded off but it was before Peterhead. What saved me from demotion, probably would not have been sacked being single pilot, was a Summer storm, and lightning knocked out the airports radar. Standard procedure when this happens is to overfly the airport on the same heading and altitude which ensures separation until it is sorted out. I think the thunder woke me up, by which time they were recalling the aircraft in turn for landing.
Sometimes you take the elevator, sometimes you take the shaft........
tut
Re: Pilot error
Wore them when getting in and out of the helicopter, but took them off in flight.
Never wore socks.
tut
Never wore socks.
tut
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Re: Pilot error
I read one report in a tabloid where a survivor reported a large bang, then the chasis stating to twist all before it hit the water, and I know another one of the survivors was taken to one side and has improved his lot quite considerably by agreeing not to talk to anyone about it.
(they never quite said the payment was for keeping quiet, but it was heavily implied)
Doesn't neccessaryily mean anything has been covered up though, just they like to keep all the info to themselves.
(they never quite said the payment was for keeping quiet, but it was heavily implied)
Doesn't neccessaryily mean anything has been covered up though, just they like to keep all the info to themselves.
Re: Pilot error
An AAIB is gospel, they have all the information from both the Flight Recorder and the Voice Recorder, together with the interviews with the two pilots.
Neither the manufacturer, operator, or any third party have any influence over the findings. It had to be pilot error or AOG as soon as they started flying again so quickly. They were grounded for months after the gearbox failures.
tut
Neither the manufacturer, operator, or any third party have any influence over the findings. It had to be pilot error or AOG as soon as they started flying again so quickly. They were grounded for months after the gearbox failures.
tut