A different take on Vuichard
605carsten,
the 6ft incident was down to a basic altimetry error. Quite a wake up to realise that for all the sophistication of GNSS, PBN and RNP, an ATC screw up and lack of crew awareness could nearly bring the house down.
Could a sim scenario train against this? You bet.
Basic flying skills still matter and show. The AFCS requires more skill, it isn’t a substitute. Both need to be trained and tested.
the 6ft incident was down to a basic altimetry error. Quite a wake up to realise that for all the sophistication of GNSS, PBN and RNP, an ATC screw up and lack of crew awareness could nearly bring the house down.
Could a sim scenario train against this? You bet.
Basic flying skills still matter and show. The AFCS requires more skill, it isn’t a substitute. Both need to be trained and tested.
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For example if you were cutting a base line for a power line and the next turning point was miles away you set up the laser on the turning point and climbed until the surveyor could see you. You then hovered there until he “took the shot, later on we mounted reflectors on the cowling front and sides so he could get a laser range too. .
The surveyor now could direct the line cutters on the correct path.
In hilly terrain that could be 3000 feet or more. I think the highest shot I did was 7000+, at that height the laser “dot” filled just about the entire screen.
If the laser was set up in soft ground you had to tell people near it not to walk around as it could cause the tripod to move which caused the stabilization to kick in and the dot would move in the screen causing you to think the helicopter was moving and make a correction.
If you lost the dot you had to descend well away from the beam as you didn’t want to be looking down and accidentally look into a 10 amp laser beam.
You tried not to use pedal much and soon discovered that ( into Wind ) a little collective up moved you forward and down moved you back so you used that a bit. The whole thing was muscle memory and constant practice was required which the client paid for.
It was common to turn slowly as you climbed and discover when you had a chance to look around that you had turned 60 degrees or more.
You could encounter rapid changes in winds aloft as you climbed at +- 1000 fpm and be blown “off the spot”. So you would, on your next attempt, slow your rate of climb to transition more slowly coming through the area of change.
Coming down after the shot we would just lay it on its side and peg the VSI.
It was a fun job. Great crews to work with.
I will probably get a lot of flak for this but this is a combination of 2 posts on the old discussion.
I am posting a couple of photos just to relieve the monotony.
I was doing a job which entailed a lot of climbing, descending and hovering at high altitudes AGL.
I discovered that it is possible to enter VRS from a steady hover.
I am posting a couple of photos just to relieve the monotony.
I was doing a job which entailed a lot of climbing, descending and hovering at high altitudes AGL.
I discovered that it is possible to enter VRS from a steady hover.
It will also drop you straight into VRS if you engage GTC-H (Ground Trajectory Control - Hover) from forward flight with a low power setting as engaging GTC-H does not automatically engage a Vertical axis.
You need relatively calm conditions of course. Not an issue if you have taken the time to actually read the AFCS FOBN.
Ground Trajectory Command in Hover mode (GTC.H)
The Ground Trajectory Command in Hover (GTC.H) mode is designed assist the pilot in acquiring and maintaining hover.
The Ground Trajectory Command in Hover (GTC.H) mode is designed assist the pilot in acquiring and maintaining hover.
- – When engaged from forward flight, the mode will acquire zero ground speed.
- – In hover, the GTC.H mode maintains zero ground speed and constant heading when the cyclic stick and pedals are released.
The GTC.H can significantly reduce the pilot workload to maintain an accurate hover position, especially if the visual references are poor.
The GTC.H mode does not manage the vertical axis. The pilot must manually control the height/altitude or add a vertical mode (e.g. ALT or CRHT) when operating in GTC.H mode.
When GTC.H is engaged at a low power setting, failure to manage the vertical axis could result in a vertical descent and possible entry into vortex ring conditions!
But if you do engage collective axis autopilot with GTC.H (or any other mode), the Helionix will keep the helicoper out of VRS-region regardless of how much rate of descend pilot asks for.
well, its a proven thing in the fixed wing world, the chopper world is woefully behind in that area,
VR is a great training tool for some things but it would suffer from the same issues - accurately reproducing handling qualities in hazardous scenarios.
You can do the same these days with any Airbus Helionix equipped aircraft automatically which will hold ~ +- 1 metre with good DGPS data.
It will also drop you straight into VRS if you engage GTC-H (Ground Trajectory Control - Hover) from forward flight with a low power setting as engaging GTC-H does not automatically engage a Vertical axis.
You need relatively calm conditions of course. Not an issue if you have taken the time to actually read the AFCS FOBN.
It will also drop you straight into VRS if you engage GTC-H (Ground Trajectory Control - Hover) from forward flight with a low power setting as engaging GTC-H does not automatically engage a Vertical axis.
You need relatively calm conditions of course. Not an issue if you have taken the time to actually read the AFCS FOBN.
The system was pre GPS and it was all hand flown.
When I originally talked about it with reference to entering VRS from a stable hover in these specific circumstances, ( very stable hover, OGE, extended time in the hover, no wind, no turbulence or down draughts etc) more than a few folks violently disagreed and stated that you could not enter VRS from a stable hover in calm wind conditions. Since then I have seen some of these same folks state with some authority that you can
One thing I never encountered was any sort of violent aircraft movements, unusual attitudes, torque fluctuations or vibrations. Just sloppy controls and an exhilarating rate of descent which could be increased with an increase in power. I sometimes spent up to 2 minutes in this flight regime as I had to descend back to ground level to reacquire the laser dot again anyway. I would exit the VRS with a 45 degree exit with power applied…worked every time. You would feel a bump as you exited (much like flying through your wake when doing. a 360 steep turn ) . Fun daze.
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Last edited by albatross; 8th Apr 2024 at 14:21.
It will also drop you straight into VRS if you engage GTC-H (Ground Trajectory Control - Hover) from forward flight with a low power setting as engaging GTC-H does not automatically engage a Vertical axis.
You need relatively calm conditions of course. Not an issue if you have taken the time to actually read the AFCS FOBN.
Originally Posted by [email protected]
No, the problem is that helicopters are far more difficult to model than FW and although you can make a generic model, accurately reproducing a particular aircraft requires accurate data from a fully instrumented real aircraft and no-one is going to pay to explore VRS in an expensive helicopter.
VR is a great training tool for some things but it would suffer from the same issues - accurately reproducing handling qualities in hazardous scenarios.
VR is a great training tool for some things but it would suffer from the same issues - accurately reproducing handling qualities in hazardous scenarios.
I dont know how many times I have sat in a Level-D sim thinking that the damn thing does not fly like the real thing. My point is that its better than nothing as its akin to not teaching spin recovery to PPL students except have a quick chat about it. Same here. VR and modern tech has its advantages in certain training exercises in the same way you have to teach upset recovery in a real airplane as being upside down in real life is more unsettling than in a sim, but again doing all this in a Citabria is a whole lot easier than a 737also, so somewhat limited use also.
Vortex ring protection is only applicable with a vertical axis engaged which does not occur with selection of GTC-H from forward flight unless you add a vertical mode manually.
