Skydive Pilots Around??

[BritishGuy]

I really appreciate the advice ladies and gentlemen. I went and got one other pilot to take me out the other day and give me a practice run and we had a few guys hanging of the wings and doing all sorts.....he showed me exactly what has to be done to keep it up (the plane that is!) I felt a lot more comfortable afterwards. Todays tandem jumps went a hell of a lot better. More confident, controling the aircraft (as opposed to the other way around) it felt good. Bu tyeah, I understand, I don't want to get complacent. I still have a lot to come I guess and have to be ready for anything. But thanks all the more.

 

[TonyC]

Spend some time thinking about your engine and how you're going to treat it on the descent, and make a pact between yourself and the skydive Gods that you will NEVER make an idle power descent, or push the limits of yourself, the engine, or the airplane.

Yo, Avbug...

I've never carried jumpers, and likely never will. But just for the sake of my curiosity, and for those others out there too afraid to ask, what's the harm of an idle descent?

 

[avbug]

Why not do an idle decent in a piston powered airplane?

You're joking, right??

 

[Tug Driver]

are we talking about "shock cooling?"

 

[huncowboy]

"shock cooling?"

happened to me yesterday after opening the fridge and locating a missing Warsteiner behind some potatoes...

btw that comment about the brakes and the black eye cracked me up... would have never thought of it but I can imagine the guy stepping on it than doing the superman thing lol... guess it is not funny but I am still laughing...

 

[avbug]

Slipping off the step can be humerous, but it can also hurt. Spin off feet first to the rear, and a concussion can result, not to mention the possibility of grabbing a cutaway handle or a reserve handle while reaching for grips on the step. Sometimes it's a joke, but not when someone gets hurt.

Idle descents can cause thermal damage. Call it "shock cooling" if you will; I've changed enough cracked cylinders to have a healthy respect for the potential cosequences. Backlash damage to engine accessory drives and to the engine itself, any time the slipstream is driving the propeller, is also a real factor to consider. Idle descents in a piston airplane are stupid things to do, smack of exceptionally poor airmanship, and can quickly unnecessarily reduce the life of the engine or it's components.

Sadly the time it's most likely to be manifest isn't in the shop during an inspection; it's during a hot and heavy takeoff with an airplane full of student skydivers.

 

[TonyC]

Why not do an idle decent in a piston powered airplane?

You're joking, right??

NO, I was dead serious. That's why I asked the question, EVEN at the risk of being ridiculed. Thanks for not letting me down.

 

[Tug Driver]

so if one doesn't utilize idle decents, how would one practice engine out procedures?

 

[avbug]

There's a big difference between doing an idle descent from eighteen thousandfeet, or twelvethousand feet (whatever is being used for jumping on a given day), and a training occasional maneuver.

I did some work on a 182 last year that had been with a particular jump operation for a decade. In reviewing the logs, seldom had it gone fifty hours without a cylinder change. That wasn't due to improper installations, or severely bad maintenance. It was due to too many full power climbs with not enough cooling airflow, and too many power off descents...not to mention very likely poor mixture practices.

Pulling the power to idle is hard on an engine, period. Making a comparison between training operations, and operational flying, isn't a good one. In the former, we're attempting to briefly show a slice of what could happen, and in the latter, we're into the every day methods of how it should happen. Big difference.

Additionally, why would you stress the airplane any more than necessary?

 

[huncowboy]

so if one doesn't utilize idle decents, how would one practice engine out procedures?

I >>think<< what avbug means by idle descents is when you come down kind of fast with idle for an extended time from a higher altitude. If he meant something else he will surely correct me.

When you're practicing engine out, you typically begin from 1500-2000' or even lower. Of course you can do it from higher but there is no point in spending training $$ for keeping that 70KIAS for X minutes longer while you are done with all the procedures.
Another thing is that when you practice engine out you pitch for a relatively slow airspeed that may not give such a cooling rate. But in winter I can imagine even a 2-3 min descent at 70KIAS can cool the engine extensively.

During my training, so far, the only maneuver that always resulted in the cylinder gauge needle hitting the left side of the scale was emergency descents.

As always: I hope someone will correct me if I was wrong with the above.