sweetjane
15th Jul 2010, 08:55
Gotta do a BFR tomorrow and am reading over some old theory notes..got to the section on power checks prior to operating in confined areas at high density altitudes. There's a section in the theory I'm not sure I understand with regards to flight ops.
On a R44 the margin required between maximum manifold pressure and conducting a hover OGE is 6". Best rate of climb is 53kts. So say the charts say at 3000ft density altitude , 25 deg OAT the max MAP is 26" Assume the pad is at 3000ft AGL I can safely land if the chopper will maintain straight and level at 53kts and 20" of manifold pressure i.e the max MAP of 26" less the 6" of margin for an out of ground effect hover and 53kts is best rate of climb..right?
Ok here's the bit I don't get ..the theory manual says having confirmed the maximum manifold pressure off the charts confirm this by increasing the collective to the maximum without observing a drop in RRPM. What it doesn't say is what flight condition I should be in when when checking this ..I presume straight and level as a climb will reduce RRPM and I presume I start at VNO?
The thing that seems erroneous about the instructions in the theory manual is if I pull max MAP in straight and level then I imagine I would soon be outsde the limitations within the 44's flight manual ..which says never exceed 100kts IAS when operating at max MAP.. ..which makes sense to me as I'd imagine with low fuel, low weight if you pull max MAP you'd be soon getting close to VNE?
On a R44 the margin required between maximum manifold pressure and conducting a hover OGE is 6". Best rate of climb is 53kts. So say the charts say at 3000ft density altitude , 25 deg OAT the max MAP is 26" Assume the pad is at 3000ft AGL I can safely land if the chopper will maintain straight and level at 53kts and 20" of manifold pressure i.e the max MAP of 26" less the 6" of margin for an out of ground effect hover and 53kts is best rate of climb..right?
Ok here's the bit I don't get ..the theory manual says having confirmed the maximum manifold pressure off the charts confirm this by increasing the collective to the maximum without observing a drop in RRPM. What it doesn't say is what flight condition I should be in when when checking this ..I presume straight and level as a climb will reduce RRPM and I presume I start at VNO?
The thing that seems erroneous about the instructions in the theory manual is if I pull max MAP in straight and level then I imagine I would soon be outsde the limitations within the 44's flight manual ..which says never exceed 100kts IAS when operating at max MAP.. ..which makes sense to me as I'd imagine with low fuel, low weight if you pull max MAP you'd be soon getting close to VNE?