I'm a pre-solo student working on an add-on commercial rating to my fixed wing ATP.
I have about 25 hours, all in the R44. My question is about "power checks", spurred by other recent discussion topics on this forum.
The R44 performance charts are pretty meager, and just include IGE and OGE hover charts, but don't include the expected manifold pressure settings (charts are a function of altitude, temperature, and weight).
My hypothetical oral question would be something as follows:
You takeoff from sea level at 15 degrees in an R44 loaded to 2300 lb.
Your destination is a confined area mountain top helipad surround by 50 foot trees at 4000 ft elevation and 10 degrees. It will take 30 minutes to arrive (landing weight 2250 lbs). How do you know you can land on the moutain then takeoff again safely at the destination?
My answer, I suppose would be a combination of:
1) Consulting the Robinson POH OGE hover chart and making sure I could hover OGE at 4000 MSL 10 degrees at a weight of 2250 (chart says I could, with only a 25 pound margin).
2) High surveillance power check at 55 knots and 500 ft MSL. If I have 5" of mainfold pressure remaining to max takeoff power during high surveillance, power check is OK.
My other question is, once I had landed on the mountain, is there a rule of thumb for a power check during an IGE hover prior to subsequent max p. takeoff? I.e. If I'm hovering IGE on the mountain and have 3"(?) remaining to max takofff power, should I be able to successfully perform a maximum performance takeoff? I just made up the 3" because at a given weght, there seems to be about a 3000 foot difference between maximum IGE and OGE altitudes, and you lose roughly 1" of manifold pressure per thousand feet MSL in a normally aspirated engine.
Thanks for any help or guidance. I did ask my instructor and they just replied with the high surveillance 500 AGL 55 knot 5" margin power check and didn't elaborate.