G'day Sasless, long time no see, in fact thought I saw you the other day, in a doco on the bridge built just downstream of the Hoover Dam. They had a Huey come by to run the first cable over, reckoned the driver had been flying since before Pontius????
Back to thread - whilst I respect your position I disagree, in fact I believe It's a dangerous adage to be trotting out. Firstly I know of none who have been killed by low RRPM doing an auto. If the auto RRPM is set up correctly it is impossible to have too low an RRPM if correct technique is used. Plenty in fact many, have been killed by allowing their RRPM to decay way too low for reasons other than a simple EOL. It is quite simple to have low RRPM, leave the lever up and do not apply enough power to drive the rotor.
I believe the potential for injury in an auto is far greater with a high auto RRPM set up and have the back to prove it.
The thing is students must lower the collective right away straight down to the bottom. Do that at low altitude with a high set auto RPM without time to adjust and hey presto High ROD. High ROD is what hurts in auto. A higher than acceptable ROD will ensue even before the RRPM tops out. That is not acceptable.
Say a pilot has high set auto RPM with a light load he has the lever say a third the way up to maintain what he thinks is an acceptable RRPM, but he will have a higher than acceptable ROD with only two thirds the lever to arrest descent, that is not acceptable.
Say he has the lever full down with the RRPM at the top, you can absolutely guarantee that he will have a much higher ROD which will take more than the full lever to slow down.
Under the same high set auto RPM with MAUW the lever will be well up to keep the RRPM in the green, I ask you, would it not be better to have had the auto RPM set up as per the manufacturer where it will have the best configuration of full lever available and the lowest ROD as possible or - be risking a safe touchdown with only a small amount of lever to slow down a heavy aircraft. Your loved ones may be on board?
We've done all the experiments and arrived at the one correct conclusion, set it up as per the book, make sure students react as per the book, Low ROD is KING.
This was strongly brought home to me after my situation where I was loaded just at MAUW, rain dripping everywhere (R22) and hot as hell. Just after take off and just starting to translate above the forty foot trees, some water in the fuel found the carby. There is only one rule, I followed it - Lever instant full down -heavy touchdown, I distinctly remember feeling that it was pulling me down way too quick. At touchdown the ELT went off in my headset way before the RRPM came back low enough to set off the low warning horn. Yet I had the lever full up from that one-pull at about eight feet, I can assure you, no doubt about that. The full lever just simply did not slow me down enough, why?
Upon checking later with the rest of the crew, Aw yeah that one was a bit high we meant to adjust at the next 100. Thank you so much, took me a full year to pick up two full Jerry cans, and nearly two years to pick up one only.
I feel so strongly about it now that I believe any helicopter not rigged as per the book should be grounded until rectified, in the heat of the moment at low level you just cannot compensate and anyway what's the point of compensating to give you less lever to save yourself, a no brainer really, especially if its been there done that.
I further believe that any FOI who does not check and ground if necessary before conducting any proficiency check is severely derelict in his duties and self.preservation. The word will soon spread - fix it properly.
Another reason for correct rigging is correct throttle correlation. Another day way back when I started flying I got caught going down too quick in G2, and at full lever it continued - down, would not over pitch. Result - hit a tree with the sync elevator and broke it but maintained control,. Would have been far better to have been able to over pitch for a second to avoid the blessed tree, as it would have to help me in the auto described above.
Cheers tet.
Last edited by topendtorque; 30th May 2013 at 19:42.