Originally Posted by
paco
Trying to get up a discussion subject for a CRM course - if you were having to nurse a helicopter back on low fuel, are you better off reducing power and beeping the rotor RPM down to the bottom of the green range or pulling as much power as you can, on the basis that the (turbine) engine's best power is in the high range anyway and that you get a higher percentage of groundspeed against airspeed?
Answers on a postcard please.....
Phil
Gidday Phil,
Been there, done that, so here's my 2 cents worth. I think our pal OLDBEEFER has the right idea, but in my case (halfway between Kalgoorlie and Warburton) or ANY case in the 90% of Australia which is going to KILL you if you land there, I think other options are in order.
In my case, winds were exactly opposite those forecast...got to the PNR for Kal and had enough fuel to continue (just) with reserves intact...almost immediately the winds got worse...calculated a last point of diversion...got there, all good, crack on! AGAIN the winds get worse. If you've never been in that part of the country then let me tell you, landing is an option of last resort. We eased the aircraft up to max range speed (way back when fuel first started looking iffy) but that wasn't enough. Eased the altitude up looking for better winds...a little better. My copilots fingers were flying on the whiz wheel...with the slightly better winds our fuel looked to be right on the margin...perhaps breaking the reserve fuel, but still getting there with SOME fuel. Long story short, we ended up getting a little help with better winds on the last hour of the leg and got in with enough fuel to be comfortable with...however, a long and creepy leg all the same.
Now, to your question. In the Seahawk there is only one normal variable (besides turning back) and that is speed...for us, using max range speed. We discussed singling up, but the significant reduction of speed whilst operating single engine was prohibitive so that idea was scrapped. We CAN adjust Nr up or down (up to 101% or down to 96%)...the rotor system of the Seahawk operates more efficiently at 96% but its an option that we aren't really all that well versed at so I wasn't really keen to experiment in the real case...I suspect that if we had beeped Nr down to 96 we would've gained a slight advantage.
We did a few other things that might have just got us over the line (might not matter depending on the type you are flying at the time...for example, we made sure our APU was shutdown (burns 150lb/hr)...we also shut down the ECS (environmental control system...air conditioner)...this uses bleed air and we wanted ALL the power of those engines for flying. I'd suggest that if you can afford for engine anti ice, or any other bleed air option to be off, thats the place for it to be in the 'tight fuel' scenario.
In the case where you're going to a ship (as in the Navy option) then the sooner you let 'mother' know you're in dire straits the sooner she can start making way toward you.
I'll just add that the maintainers we had riding in the back were blissfully unaware that we were sweating our green suited asses off in front...the only point here is that those guys put complete faith in us when they hop in...I guess we need to consider CAREFULLY why we're going and if there is any urgency to get there...in my case, we did all the proper flight planning, had plenty of fuel to go and the scenario just kept deteriorating and deteriorating...it seems that we kept plowing on and on, but at every 'checkpiont' along the way we had our required fuel plus reserves intact...it was only when we were PAST those critical points that things further degenerated...the point, I guess, is that despite all the best planning there are factors that ARE beyond our control.
Anyway, enough of my lecturizing. Hope this was helpful in some way...even if just to give you a feeling of moral superiority over my dumass self.
Bottom line is that you MUST have a story to tell to generate discussion at these CRM courses...use mine if it is any help but if you've got one of your own (or if one of the students have one even better) get that discussion going and see what kind of CRM points you and the class can generate from the discussion.
Happy to discuss further.
HP