Originally Posted by
A Squared
Well, I'm not sure what an "ex-albert driver" is, but if we assume that you at one time flew a c-130, we have to also assume that it was a while ago, because your systems knowledge is pretty lacking. Spouting the numerical specs for the prop is not the same as understanding how it works First the prop does not have "stop pins", I don't know where you got that but there's nothing in there that could be remotely described as a "pin". Regardless, the props go into reverse at high airspeeds on almost every flight. That's what you do on landing. It doesn't activate the NTS and it doesn't decouple the prop Besides, even if it *did* decouple, that doesn't prevent the prop from going into reverse. The safety coupling has nothing to do with prop function or control, All the safety coupling does is disconnect the reduction gearbox from the turbine, the prop is still out there in reverse. You may (or may not) recall that there is nothing to prevent you from moving the throttle into the beta range in flight. All you have to do is pick the throttle up over the flight idle gate and move it back into the ground range, and the prop will got to flat pitch, then reverse. It won't NTS because the NTS linkage is cammed out of engagement when you move the throttle into the ground range. Obviously that's a really bad thing to do in flight, so you don't do that. But, here's the thing; if you have a throttle cable break, the effect on the throttle coordinator out on the engine can be essentially the same, the throttle coordinator doesn't 'know" whether the cable broke or the throttle was moved into the ground range, all it knows is something just rotated it into the reverse range, and it does what it does in the reverse range ..whcih is this: it moves linkage to the valve housing whcih causes a prop pitch change into the reverse range and it cams the NTS linkage out of engagement. There you go: One single point of failure, and you have a prop reversing in flight. This isn't just speculation or theorizing this is the actual, real, cause of actual, real inflight prop reverse incidents. It seems odd that you claim to be a C-130 pilot and don't know about this. I thought that was one of those things that all Herc crews knew about. That's why you have a special Engine Shutdown Procedure which is different than a standard ESP when there's a known or suspected throttle or condition lever cable failure. You do remember that from your "albert" days, right? That a throttle cable failure had a special procedure? It's in all the Lockheed manuals, I don't know how you could have missed it. That's the reason, because it can cause the prop to reverse in flight.
Harsh (arguably unnecessarily so), but completely correct explanation. FYI RAF C-130s were and are referred to as Fat Albert...so ExAscoteer (Ascot was the RAF Air Transport callsign) has a good deal of experience no doubt. However, prop theory was always 'tricky', and time has undoubtedly not helped........
Yes, I just about remember the T-handle shutdown rather than condition lever in the event of suspect throttle cable failure (whilst leaving the power lever/throttle well alone), but it's been a few years for me since flying our 'Super Es' (C-130E plus Dash 15 motors).
'Gentlemanly' should be the way forward.........it's too easy to misconstrue/put others' backs up on forums....
Whatever happened overcame the pilots' capacity to recover at such low altitude....RIP chaps - a dreadful way to go.