hauger said:
Fair enough...one engine. I would have thought that OEI through shutdown increases the risk of Vmca due to failure of the other engine running on that side...leaving 2 working engines on one side pulling 2 engines Inop. on the other side. Granted, it's probably safer than having 2 engines caged and then having a third pack it in while low level. Can't imagine that being fun either.
So....back to the original question, can the P-8 operate efficiently and usefully at low level, or will visual id become the domain of UAV's directed from a P-8 operating on high?
I have flown the sleek greyhound of death for some 4000 hours, and have another 2 grand on heavy jets. What the heck is OEI? Is that "One Engine Inoperative" . This is a new one for me.
Your comments about VMCA show you have a fair amount of knowledge. Cool, it's nice to read a poster with this kind of educated understanding of our world. Your statement shows good understanding, but we would be really stupid to operate the airplane with engines shutdown in the way you have stated. When we shut down one or two engines for fuel savings, there is a damn good reason to do so. Perhaps it is to try and save people in the water or to maintain contact on a bad boy sub. Or if given the chance, perhaps it will be to keep our really way-cool new camera focused on some Taliban baddies in aid of our tan CADPAT friends. Whatever the reason, if we do so it is a matter of risk assessment, weather, fuel that can be saved, options if we have an engine failure, terrain, and many other issues. Shutting down one is a fairly regular thing. On the other hand, in my many years of flying the CP-140 I have been "on two" about five times. I think three times were for SAR, and twice were for other operational reaons. As Cdn Aviator says it's a rare circumstance.
Needless to say, operating with one shut down is simple, easy, and nearly risk free. That said, we assess risk and make a call as to whether the decision is the right one or not. When we operate with two engines loitered we fly at an altitiude and airspeed that will allow us the time and space to spark up a loitered engine. We have a specified minimum altitude that we can operate at, and if heavy we will operate even higher than this regulated level. We look at the charted rate of descent on one engine, and make a call about our minimum altitide for operations. Our speed is sufficiently high that we will not reach anywhere near VMCA, provided we don't paint ourselves into a corner by violating our orders while also being stupid. Also, an engine failing doesn't "pull" unless it also fails to feather or if you are stupid and get really slow. If you have this double failure (i.e. engine failure with a failure to feather the propellor) you are having a bad day. This failure to feather scenario is extremely unlikey, but sometimes the "gamble" is worth it some days.
Lastly, who cares about VMCA unless you are trying to avoid an obstacle. Frankly, if I am above safety height I do not care one iota about my ability to maintain a compass heading. As long as I get theat other engine going, I am happy. Not many "controlling obstacles" when flying over the water, are there?
With regard to the P-8 and its suitability for overwater ops, there is a lot to be said about it's unsuitability as compared to the P-3. There is no better airframe IMHO for low level over water ops than a P-3. It's an airborne tractor; strong, easy to operate, and forgiving. However, we ain't gonna get a new P-3 since they don't build them anymore. So we are likely be stuck with what the USN will buy, which is likely the best decsion we could make. As a note for WPA, the bombardier product is not a good choice for Canada. The RAF bought them for their ASTOR programme, and despite being overbudget, the airplane has failed to meet any of their requirements. IMHO, it would be crap. Anyhow...
That's not to say that the P-8 will be unworkable in the long range patrol role. Firstly, the airplane will not need to be operated the same way. Many of the sensor ops will be more efficiently done at high altitude, because the sensors will be lightyears ahead of what we know have. In the ASW role, the only time we will need to go low is to kill something. The localization to attack criteria will be done entirely at high level. The anti-surface role will not require any low level work, unless we need to show a "presence". If we are going to shoot something, we will be able to identify a ship by hull number from scores of miles away, and kill him just as far away.
For SAR, we will need to go low. The airplane will not be as good in this role as the Aurora. But hopefully we will do this only rarely, becuase the government will have bought the AF a really good SAR platform for that purpose. If this doesn't happen, well we will just have to make do, scootin' along at about 220 knots (not 400 as you suggest) with those big hoovers sucking up gas by the tonne.
Bart
