HC,
Deck-edge clearance is dependent upon an acceleration to the RP, this is always achieved AEO. If, as discussed in the other thread, the aircraft cannot achieve this acceleration, it certainly will not be able to meet the requirements of the profile. As is commonly understood, it is kinetic (acceleration and residual rotor energy) and potential energy (height at the RP) that provide clearance from the deck-edge, and OEI power that reduces the drop down.
Exposure does not just last for a few seconds (except for aircraft which can comply with little effort or impact on cost) nor can it ever be contained within 1 x 10**-9 (unless the engines could be made super reliable - in which case we wouldn't be having this debate). With existing aircraft the risk still contains both elements - deck-edge strike, and ditching without a SFL.
With regard to ALARP there are two sides to the equation; before it can be assesed we need to move the discussion back to the operational costs. I would be interested in a re-assessment (using the figures from the RFM provided earlier) of the impact of compliance upon loads and fuel. Is it still the contention that compliance will impact detrimentally upon fuel loads or result in (more than) a 30% increase in flights?
How much endurance does the EC225 have with a take-off mass of 10,875 and 19 passengers?
DB,
I have not compared the numbers so I am not sure; AEO HOGE was the first attempt to set a minimum standard but, as HC points out, it is the combination of AEO and OEI which provides protection throughout the profile. In fact the use of thrust margins to establish take-off masses is extremely difficult to achieve, as is the provision of a simple metric establish the PC2e mass. Notwithstanding that, I still cannot see how the flight conditions stated in the low wind thread would occur with AEO HOGE power (unless someone can explain).
Jim
Last edited by JimL; 19th Feb 2010 at 13:50.