First in answer the question posed by Mars on the EC225 thread:
Within the extant JAR-OPS 3 (amendment 3 at 1st April 2004), approval to operate with exposure to an engine failure on take-off and landing lapses from 2010 and operation in Performance Class 1 (PC1) will be required. For a number of reasons (mainly concerned with the deck size and the helideck environment – both obstacle and wind related), it is not anticipated that operations in Performance Class 1 will be technically feasible or economically justifiable by that time (One Engine Inoperative (OEI), Hover Out of Ground Effect (HOGE) would be an acceptable method of compliance but this could result in a severe restriction on payload/range).
In view of this approaching deadline and the limitations discussed above, there is a need to produce a practical alternative to PC1 which will ensure that take-off/landing mass reflects: the procedure; deck-edge miss; and drop down. As accident/incident data indicates that the main hazard is collision with obstacles on the helideck due to human factors, a simple and reproducible but deterministic procedure is required. Such a procedure will require the calculation of the take-off/landing mass from information produced by manufacturers reflecting these elements. It is expected that manufacturers information will be derived from performance modelling/simulation using a model validated through limited flight testing. This alternative to PC1 for offshore operations might be termed Enhanced Performance Class 2 (PC2e).
Peter Manktelow -
Now I am not as concerned with the landing phase. With good technique , even hot and nil wind , an engine failure on approach , holds less angst for me. It is the take off that worries me….and surprise surprise …. it is NOT the single engine performance that I want , it is TWIN performance !
This subject, as a debate, was concluded some year ago and led to guidance that take-off from a helideck should only be undertaken with hover out of ground effect performance (all-engines-operating). It should be clear to all that as soon as the ground cushion is dissipated the aircraft will sink - all of us who have flown the early marks of the S76 in nil wind conditions will sympathise with your post.
It is a commonly held belief that we have more problems with power for take-off than for landing; performance modelling does not accord with this thinking and appears to indicate a greater power requirement for landing than for take-off. If one were to examine the masses for the S76C+ helideck Cat A take-off and landing, it would confirm the modelling results; however, this statement should be hedged around with qualifications as it results from an interpretation of JAR 29 that appeared to require that a single-engine landing should be possible on the helideck with a failure occurring at any stage in the approach. Perceived wisdom, confirmed by performance modelling, appears to confirm that providing Risk Assessed landing profiles are flown, the gap between take-off mass and landing mass can be narrowed. In partial answer to ‘gomex’s’ comment, such profiles are dependent upon a OEI flight back to a land base. I’m sure Nick will wish to comment on these thoughts.
Heedm - I think a helicopter company should design a twin that outperforms 412, 76, etc. in their typical roles, and has full envelope OEI. Before marketing this machine, the company should lobby all the regulatory boards and insurance companies to demand this. Then us poor operators would be left with no choice but to fly safe expensive machines.
Perhaps you might wish to follow the thread on the AB139, which appears to have this capability. With regard to your comment on lobbying, you will see that there is an attempt to describe the level playing field that you demand contained in the first two paragraphs of this post.
Steve 76 - Full Cat A availability is a only as good as the pilot on the end of the controls. You can have all the engines in the world but without the correct profile flown it is a waste of time. You still end up in the side of the rig, ocean or the side of the hospital in EMS.
None of us could have stated this better, if operational margins are to be limited to permit techniques which do provide engine failure accountability at an economically justifiable cost (be it PC1 or PC2e), the success of these techniques will be wholly dependent upon: (1) an understanding by the pilot of the risk profile of the technique; and (2) adherence by the pilot to that profile.
Steve 76 - An S76A can be flown at pretty much MAUW on a profile that will allow a single engine landing with no roll out on a rig or roof top. Take offs are another issue.
For the reasons discussed in the comment to Peter, this statement is not borne out by modelling or practical experience; whilst it may be possible to demonstrate this to a “landing square” that is drawn out on a runway, it is generally accepted by test pilots that this is not true when flying to an elevated heliport or helideck.