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Doesn't anybody fly an approach by maintaining an apparent walking pace over your toes? Positive forward motion (visually over toes and IAS), controlled rate of descent, aim point steady in the window. From 300' and 60kt, the decreasing airspeed makes the walking pace looks constant all the way to the hover where you have a REAL walking pace.
A downwind approach will have groundspeed apparently higher than indicated airspeed, something which should be detected well before losing translational lift. But people still fall out of the sky, and run out of left pedal, and do silly stuff. Like "Pretend" VRS at 100', and practising bleeding. |
Well, given that the most likely scenario for getting into VRS on approach when you think your airspeed is sufficient, is because you're in a tailwind, doing this simulation with a good amount of forward speed was correct for that type of situation. Whether you believe in the Vuichard technique or not, learn how not to get in the situation and learn to identify the early stages of onset. |
Originally Posted by Hughes500
(Post 11625980)
In my humble opinion i dont think Claude has ever been in VRS ! Having been there once I can assure you adding power to step out made it worse not better !!!!
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One problem with discussing IVRS and recovery techniques is that the incipient stage is very variable and not binary - you can go from having the right figures on the dials to believe you are at the onset of IVRS, where pretty much any recovery works, to being much deeper into the void where application of power takes you from IVRS to VRS very quickly (as Hughes 500 alludes to).
The Vuichard 'technique' works at the very early stage simply because doing pretty much anything would remove you from the parameters of IVRS - he has just made a song and dance out of it. |
The Vuichard 'technique' works at the very early stage simply because doing pretty much anything would remove you from the parameters of IVRS - he has just made a song and dance out of it. |
Originally Posted by Torquetalk
(Post 11626217)
That is a horrible accident Robbie. The pilot made a bad decision to continue for the rooftop, when they had space and height ahead to recover. The commital point was much much later than than the clear acceleration into VRS. The aircraft was also stable in VRS and not pitching, yawing and rolling, so really good conditions to recover.
Having reached the roof, the pilot slid long from one side to the other and then hit a small barrier tipping the aircraft over the edge and death. It seemed to me that the pilot and pax could still have survived the initial bad decision to go for the roof if: 1) they had lowered the collective progressively and promptly and got the weight square down on the roof. 2) running out of roof, lift the collective and hop over the barrier, at which point they would already have been out of VRS because there was no sink rate - but possibly out of the performance envelope, so it might have happened again… It was a pinnacle approach SE. If the pilot had recce’d and done a power check they might have realised that the approach was a NO GO. And was there any performance planning pre-flight? I’d hazard not. Anyway, the flight was intentionally flown downwind to get the required angle for the photo shoot, so I'm guessing they did their performance calculations. Thing is though, Robby pilots are generally only shown VRS recovery from an OGE hover, so we don't know what it looks like when we have forward movement, thus the pilot may not have even realized it, until the very end when he went to pull power to land. |
Originally Posted by Torquetalk
(Post 11626444)
The aircraft was next to a building. We see the acceleration in the video, taken at some distance and from above. I find it a stretch that the pilot was unaware that they were in a downward acceleration. In fact, I’d guess that the collective was pulled to check the acceleration and the low RRPM alarm went off. Then the pilot went for the roof to land asap. Not a good decision or IVRS response and pretty much locking in a bleak outcome.
Lot’s of supposition? Yes. But there is plenty of evidence to support that take in the video, and you say it was a downwind approach. If that is true, then going for the rooftop with a big sink rate was extremely dangerous and perhaps indicative of poor training and certainly poor airmanship. Not trying to be down on the pilot, but they did also kill their passengers. Perhaps the pilot did performance planning for that shoot and found… what? WAT chart - check HOGE power - I sincerely doubt it. And without the latter, the approach should not have been attempted downwind. Maybe it is also useful to separate out utility versus other kinds of flying. Moving out of the vortices may be a trick that is up any low level utility pilot’s bag of tricks to catch IVRS. But I doubt it has much application for public transport. And may be a method that invites false confidence and risk-taking by hour-building photoshoots. If the pilot really was unaware of the high sink rate, then they really should not have been doing what they were doing. And when it started to go South, just follow the training: lower the collective a little and attitude at the horizon until airspeed is indicated.The escape route forward seemed fine. Did IVRS in the sim for the first time in many years a while back. The TRE wanted to see more airspeed before recovery, but I saw 35 knots and that was good enough for me. It took several seconds. But surely that’s the point? See it developing and fix it. Apply the basic training and don‘t start As you no doubt know, training for VRS is done into wind on light or no wind days. Doing it downwind with a fair wind component is a different matter altogether. And may result in aircraft and occupants in a smelly heap. Aa for false confidence promoting risk taking? Lol, we already have plenty of that with all these VFR jobs in VFR only helicopters requiring an instrument rating. |
Originally Posted by Robbiee
(Post 11626427)
Thing is though, Robby pilots are generally only shown VRS recovery from an OGE hover,
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Originally Posted by Gordy
(Post 11626481)
I thought this practice ended in the late 90's. I have NEVER taught VRS from a hover. I always do a traffic pattern with a simulated floor of 1500' and on final tell the pilot to just pull the nose up to a decell and hold it, nothing else.
I got my PPL in 2003, and CPL in 2006, and throughout my training, insurance/rental checks, subsequent BFRs and six trips to the Robby Course, these past twenty some odd years, its always been done from a HOGE at around 2,000'. Wouldn't mind trying your method though. |
Gordy makes an interesting point.....as probably it is far more likely to encounter this horrid life threatening aerodynamic situation during a landing approach of some kind where the descending column of air catches up to the helicopter and begins to move forward of it.
At which point the floor falls out from under you and down you go. It can happen while hovering OGE as well. How many ways is there to encounter it....count them best you can. How about hovering IGE on a pinnacle and drift too close to the down wind side....might that be a way? Mustering.....might also provide some opportunities for it to kick off. I taught it much like Gordy....but put the aircraft into a known downwind situation at 3,000 feet AGL and then asked the Student to do as Gordy described except I asked for the victim to achieve a OGE hover as best possible on the desired heading (down wind) and indicated altitude. Nature, the laws of aerodyamics and gravity took care of the rest. Sorry....but no undies got soiled doing these maneuvers as sometimes it was very tame and others not so tame but the concern was more of realizing the controls did not have their full normal authority although they were still working in normal sense but not as one is used to them doing. One thing I did sense is that fully lowering the collective in a accelerating attitude (pitched down a bit) added stability to the rotor system. In helicopter flying I am of the opinion there is more than one right answer sometimes and that is always contingent to the many different variations of conditions affecting the situation. For instance, that is why in Test Flying....achieving the data points as set forth on the Test Card often take many repetitive attempts to get all of them accomplished in a satisfactory manner. |
I’ve not seen the R44 crash video that many have discussed on this thread. However, I’m not so sure that many of the so called ‘Vortex Ring’ crash videos are actually Vortex Ring at all.
I was always taught that Vortex Ring was a combination of Root Stall on the inner portion of the disc and loss of lift on the outboard portion of the disc due to increased induced flow caused by the vortex. As Rate of Descent increases into fully developed Vortex Ring State, the stalled portion and the vortex section have expanded laterally, potentially to meet each other, rendering the rotor system ineffective at producing lift and hence control. Please feel free to correct me if I’ve got this wrong! My reasoning is that if a Rotor disc, or more accurately a rotor blade, is experiencing Vortex Ring State, it is effectively no longer producing lift. If that’s the case, the coning angle would surely reduce? Most of the crash videos I’ve seen that are passed off as Vortex Ring State actually show an increase in coning angle, often just before impact. More a case of HTG (as a result of poor energy management and over-pitching) than VRS in my opinion. I’d be interested to see the R44 video discussed earlier if anyone can point me to a link. JJ |
This has been discussed many times before, and yes, an awful lot of accidents that people/reports say are VRS are in fact overpitching, or simply the aircraft running out of power (too heavy, downwind etc)
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Originally Posted by jellycopter
(Post 11626562)
I’ve not seen the R44 crash video that many have discussed on this thread. However, I’m not so sure that many of the so called ‘Vortex Ring’ crash videos are actually Vortex Ring at all.
I was always taught that Vortex Ring was a combination of Root Stall on the inner portion of the disc and loss of lift on the outboard portion of the disc due to increased induced flow caused by the vortex. As Rate of Descent increases into fully developed Vortex Ring State, the stalled portion and the vortex section have expanded laterally, potentially to meet each other, rendering the rotor system ineffective at producing lift and hence control. Please feel free to correct me if I’ve got this wrong! My reasoning is that if a Rotor disc, or more accurately a rotor blade, is experiencing Vortex Ring State, it is effectively no longer producing lift. If that’s the case, the coning angle would surely reduce? Most of the crash videos I’ve seen that are passed off as Vortex Ring State actually show an increase in coning angle, often just before impact. More a case of HTG (as a result of poor energy management and over-pitching) than VRS in my opinion. I’d be interested to see the R44 video discussed earlier if anyone can point me to a link. JJ |
Originally Posted by jellycopter
(Post 11626562)
I’ve not seen the R44 crash video that many have discussed on this thread. However, I’m not so sure that many of the so called ‘Vortex Ring’ crash videos are actually Vortex Ring at all.
I was always taught that Vortex Ring was a combination of Root Stall on the inner portion of the disc and loss of lift on the outboard portion of the disc due to increased induced flow caused by the vortex. As Rate of Descent increases into fully developed Vortex Ring State, the stalled portion and the vortex section have expanded laterally, potentially to meet each other, rendering the rotor system ineffective at producing lift and hence control. Please feel free to correct me if I’ve got this wrong! My reasoning is that if a Rotor disc, or more accurately a rotor blade, is experiencing Vortex Ring State, it is effectively no longer producing lift. If that’s the case, the coning angle would surely reduce? Most of the crash videos I’ve seen that are passed off as Vortex Ring State actually show an increase in coning angle, often just before impact. More a case of HTG (as a result of poor energy management and over-pitching) than VRS in my opinion. I’d be interested to see the R44 video discussed earlier if anyone can point me to a link. JJ I certainly agree about the cause of many accidents not being VRS - underpowered helicopters are far more likely to run out of puff trying to manoeuvre in and around HOGE and end up overpitching as a result. Granted, the end game in each case is usually a broken helicopter. |
Originally Posted by SASless
(Post 11626505)
Gordy makes an interesting point.....as probably it is far more likely to encounter this horrid life threatening aerodynamic situation during a landing approach of some kind where the descending column of air catches up to the helicopter and begins to move forward of it.
At which point the floor falls out from under you and down you go. It can happen while hovering OGE as well. How many ways is there to encounter it....count them best you can. How about hovering IGE on a pinnacle and drift too close to the down wind side....might that be a way? Mustering.....might also provide some opportunities for it to kick off. I taught it much like Gordy....but put the aircraft into a known downwind situation at 3,000 feet AGL and then asked the Student to do as Gordy described except I asked for the victim to achieve a OGE hover as best possible on the desired heading (down wind) and indicated altitude. Nature, the laws of aerodyamics and gravity took care of the rest. Sorry....but no undies got soiled doing these maneuvers as sometimes it was very tame and others not so tame but the concern was more of realizing the controls did not have their full normal authority although they were still working in normal sense but not as one is used to them doing. |
Originally Posted by Gordy
(Post 11627028)
Exactly, when doing buckets on a 100’ line into the dip sites on cloudy days, you are on the edge of it all the way in the latter portions of the approach. I need pilots to recognize the incipient nature and make a cyclic adjustment without losing more than 20’ of altitude. It can be done, we sit right on the edge in training and go in and out of the start of it multiple times on one training event.
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Originally Posted by Hughes500
(Post 11625980)
In my humble opinion i dont think Claude has ever been in VRS ! Having been there once I can assure you adding power to step out made it worse not better !!!!
what increasing power does though, I assume, is increase your torque and consequently tail rotor pitch, and therefore your lateral slip stream. Even if you main rotor is stalled and cyclic controlability degraded, the tail rotor is perfectly fine to help you step out of the VRS. I thought that was the whole principle of the Vuishard recovery. |
what increasing power does though, I assume, is increase your torque and consequently tail rotor pitch Vuichard's technique relies on cross controlling to sideslip out of the vortex - you need cyclic and yaw inputs since a yaw input alone will just turn the nose. |
"I am very concerned about the dramatic increase in helicopter accidents in Europe in recent weeks. We must learn from this that unfortunately we cannot improve the skills of pilots and flight instructors through administrative processes in one way or another. The current over-regulation in Europe ultimately leads to the opposite. We cannot improve the skills of pilots and in any way through thousands of pages of operations and training manuals, audits, quality systems and checks. The solution to rapidly reducing these accidents can only be achieved through efficient, evidence-based training in modern simulators." Apparently simulators are the only hope at preventing accidents? |
'without all that paperwork, regulations, inspections, etc....how does one think the Jobsworths at mulitiple levels of government can earn a living then retire with a nice pension?
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