Correct 212, we have two options for an EFATO, either standard EOP which is ignore the SID and climb straight ahead - MAN is a particularly good example since the SID is based on Noise Abatement and not Obstacle Clearance, of course once we had done the AN bit we could C communicate with ATC to tell them we are continuing straight ahead which is exactly what the birdstrike crews did. We also have to consider Approach Climb Gradient for an arrival which despite it's confusing title describes the Missed Approach profile with the loss of a critical engine. If the Approach Climb Gradient requirement is high as is required in HGK we have a couple of options, either raise the MDA so the obstacle is no longer limiting, or use the EOSID lateral requirement to navigate around the obstacle.
For places like ZRH the EOSIDS can be quite demanding. Our performance departments do the calculation for us and they are presented to us on the Take-Off performance computer. We then tend to construct a couple of lines in the Navigation Displays as a reminder of what to do should the engine stop which are not picked up by the NAV system but have to be flown in selected modes. Some operators have EOSIDS programmed into the FMS to call upon should the occasion arise. Just as a flavour the ZRH EOSID on RWY16 was: At KLO 2.2D, left TRK 128, Intercept KLO 141R Outbound, at KLO 4.6D, Left (190 KIAS) to KLO, Intercept KLO 253R. Hold S/W at KLO 21.0D 073 Right Turns 1 min legs.
Another issue which is largely ignored is the lateral navigation issue. Wind will help helicopters achieve excellent gradients however the same wind can easily take the helicopter out of the protected Take-Off Flight Path, this is surprisingly small, starting at 90m from the runway centre line at the end of TODA, then expanding at 12.5% until a corridor of 300m from the runway extended centre line (with sufficient navaid accuracy). Since the G/A is typically done before the threshold of the runway, straying out of the protected area is 'dead' easy. I have had direct experience with this when conducting a instrument training exercise at SUM we did a G/A, ATC instructed us to maintain RWY HDG and the 50 kt crosswind got us interestingly close to Fitful Head.
BTW only 1 'd' in Thridle!
Last edited by Thridle Op Des; 17th Apr 2009 at 18:09.
Reason: cos pprune doesn't allow you to see the original message when you reply, so I always forget something!