paco,
I think that I have already covered your question in my first post:
Category A also requires the provision of performance data so that One Engine Inoperative (OEI) obstacle clearance from take-off, through climb, cruise and landing can be calculated; this data includes: mass related take-off and landing procedures; heliport/helideck size limitations; distances and climb gradients (or rates of climb); and one-engine inoperative climb performance graphs. From these procedures and graphs an operator/pilot can establish a complete OEI flight trajectory.
and is the provision of procedures, masses and data in compliance with the respective rules of FAR/JAR 29.45 - 29.67 to the satisfaction of the Certificating Authority. This set of rules specify (along with the guidance in AC 29-2C): no descent below 15ft (when the TDP is above 15ft) in the take-off path; require a level surface over which the take-off is being conducted; no obstacles in the 'Takeoff path'; the provision of the minimum climb performance - i.e. 100ft/min up to 200ft at Vtoss and 150ft/min at 1000ft at Vy; and the provision of the respective distances. None of that is in question, the point that was being made was more fundamental - when, what and how?
When is the operator
required to apply the performance data, what obstacle clearance has to be shown and where is that specified? Clearly there is a difference of opinion as the highlighted section in the definition of Category A between the FAA and the JAA/ICAO indicates:
(JAA) Category A, with respect to rotorcraft, means a multi-engined rotorcraft designed with engine and system isolation features specified in JAR–27 / JAR–29 and capable of operations using take-off and landing data scheduled under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight or safe rejected take-off in the event of engine failure.
(FAA) Category A, with respect to transport category rotorcraft, means multiengine rotorcraft designed with engine and system isolation features specified in Part 29 and utilizing scheduled takeoff and landing operations under a critical engine failure concept which assures adequate designated surface area and adequate performance capability for continued safe flight in the event of engine failure.
The JAA clearly believes that the provision of performance data must be supplemented by the appropriate operating rules in the JARs. The FAA does not as there are no helicopter performance rules in FAR 91 or 135 (unlike Appendix A to FAR 135 for 10 or more passenger airplanes).
It is the
operational regulation which must indicate how an operation can be conducted; certainly JAR-OPS contains not only the indication when to operate within a certain Performance Class but also provides the requirements, compliance with which will give appropriate obstacle clearance in PC1 (and PC2 - outside of the take-off and landing phases).
In the absence of performance rules in the operational FARs, the FAA have to rely upon an interpretation of FAR 29.1 and in particular FAR 29.1(c):
The are a number of points raised by this approach: what rules apply to helicopters below that weight or with less passenger seats; and is the implication of this text that such helicopters must be operated only in PC1? The use of the language
Category A rotorcraft might indicate that such helicopters will have to apply the Category A procedure - at least for every take-off and landing; I’m sure that
was the intent when this text was amended on the 31st January 1983 (see the question posed by Mars on the last Category A thread that was answered by GLSNightPilot
here). The problem that this latter point poses can be seen only too clearly when examining its implication to the S92 and the EC225. Clearly both of these helicopters are being positioned for use in offshore operations and if operations are reliant upon an interpretation of FAR 29.1(c), a Category A procedure will have to be provided
and used when operating to helidecks.
All who followed the debate on the earlier thread will understand the implication of that. This is not a problem with JAR-OPS as operations in Performance Class 2 can be conducted when the number of passenger seats is 19 or below. For operations under FARs this has also been set aside for the time being with the issue of OpSpec H100 - which in other terms, specifies PC2 for offshore operations.
212man,
Yes on re-reading my earlier post I gave the wrong impression - it is only the engines that are controlled.
Jim
PS Edited on 18th April for clarity.