the 609 would be used for really deepwater rigs, the ones that are (or will be) beyond the practical range of existing helicopters.
That is correct. In general the practicality of the civil tiltrotor only comes into play when two criteria are met:
1) A requirement for vertical take off or landing exists at one end of the trips flown routinely (otherwise a turbo-prop aeroplane would be more economical if flying from airport to airport).
2) Routine flights require a normal minimum distance of 150 or 200nm plus (otherwise a helicopter would be more economical).
Tiltrotors are a niche aircraft, they will not replace airplanes and they will not replace helicopters, but they will perform missions that no other a/c can do as efficiently. A good example was given to me by a couple of guys working at Heli One. They approached Sikorsky to determine how they could perform remote arctic flights in an S-92 over a distance of 600nm to a drilling rig and return. Sikorsky devised a potential recommendation to have fuel stored in the passenger cabin to complete the flight (maybe not considered a safety hazard by the Russian authorities?). However, as a consequence of the added fuel weight they would be limited to 7 to 9 passengers. A mission that the 609 could accomplish more efficiently.
What is the emergency procedure for loss of oil pressure in one of the 609's engines?
If you were enroute the situation would be handled by routine checklist use. If the low oil pressure was accompanied by high oil temperature and/or the appropriate CAS warning the engine would be shut down and the flight continued to a safe landing location. The difference between a fixed-wing a/c and a tiltrotor is that it does not exhibit the same asymmetrical thrust in OEI ops that would occur in an aeroplane due to the fact that the proprotors are interconnected via a cross shaft that allows both sides to continue turning at the same steady RPM with the remaining engine driving them.
FH1100,
Both very basic but normal questions you raise. It's good that this time you are not trying to pretend to be an expert on tiltrotors (or helicopters, or aeroplanes). You still have a lot of unanswered questions that were posed to you in response to some of the astonishing statements you made on the V-22 thread. There are some there still anxiously awaiting your enlightening responses. As a reminder, here are the questions pending your answers (scroll down about half way):
http://www.pprune.org/rotorheads/204...osprey-71.html
thanks...
21stC