Power-off glide?

[norskman2]

Power-off landings

Back to the original idea: power-off landings.

I've had some instructors who expoused this idea mentioned earlier that every approach should be set up so that if you should lose power at any time, you should be able to complete the landing.

I understand this business about the back-side of the power curve etc., but still not sure if I get it. If I were to suddenly lose power completely, wouldn't my rate of descent increase? Or does the back side of power curve mean that I extend my glide path. Does this require a different airspeed from the approach speed?

Thanks for helping clear this up.

 

[avbug]

TD,

What make/model engine are you flying that's only getting 500 hours? What kind of overhaul is being performed? What type of aircraft, and what kind of operation? What experience level for the pilots?

 

[TDTURBO]

Good post avbug,

I think were getting caught up in semantics instead of substance. I understand what you are saying and feel we are on the same page.

 

[TDTURBO]

avbug,

I was using the 500 hrs an example of a common TBO for a small plane. If you're not making it to TBO and replacing major components at 500hrs on a 2000hr TBO engine, somethings wrong. When I say shock cooling doesn't effect TBO in a normally aspirated small engine, I realize it doesn't change the factory given #, only the ability to reach that #, therefor effecting that engines TO BE OVERHAUL time. Like I said, semantics.

 

[FlyinBrian]

I think AvBug's point is that "making TBO" is not necessarily a good measurement of how well an engine is cared for. TBO is fairly arbitrary, and a well maintained and properly operated engine can make it well beyond TBO.

 

[surplus1]

Avbug

Thanks for your answer, I guessed as much. I agree with most of what you've said about the care and feeding of recips. Sounds like you may have been and FE from the period when FE's were for real.

My 135 experience is virtually nill and its been a long time since I've flown light airplanes so I'm not up on the engine types you all have been discussing.

Agree with what you say about TBO. I know that under 121 the same engine type often has different ovehaul requirements based on the operator's experience with that power plant. It's an arbitrary number as you point out.

I spent a lot of time with the R-985, 1830, 2800, 3350 and 4360. The latter absolutely fascinates me. How so many moving parts all going in opposing directions could stay together is amazing.

The first time a blown jug tares a gaping hole in your cowling and departs your enviornment forever, you get a good appreation of what can happen to recips if you don't pay attention.

I have a nostalgia for the big round engines, but I love the simplicity of the fan jets and the very high reliability. BTW, they too start out with TBO's that change to on condition with both engine longevity and operator experience.

You've put out a lot of excellent advice and information on engine operation. Congratulations.

Just so it doesn't go to your head, I have seen some of your piloting recommendations not quite as stellar. (LOL) Just pulling your chain.

Are you currently working as an airman?

 

[avbug]

TBO means "Time Before Overhaul", and is set; it is immutable. It doesn't change, except by ammendment from the manufacturer. It is not arbitrary, nor does it vary. It is set, fixed. It is a designation, much like the designation of the engine itself. If an IO-360 engine is destroyed in a crash, it still remains an IO-360 engine. If that engine has a 1,600 hour TBO but is overhauled at 300 hours, it still has a 1,600 hour TBO. TBO doesn't change, and once the overhaul has taken place, it's no longer valid.

Overhauls take many forms, and except for a factory remanufactur or overhaul, TBO doesn't get reset following the overhaul.

Time is then reconed as time since overhaul, typically expressed as STOH (since top overhaul), or SMOH (since major overhaul). Some erroeously believe that once an engine is overhauled, it can "go to TBO" again. However, TBO stays the same. It will get surpassed, and no longer applies; it's a moot point.

500 hours isn't a common example for TBO on light aircraft. Some TBO's are as low as 1,200 hours, most are 1,600 to 1,800 hours, and a few as high as 2,400 hours.

The question was posed of weather doing a top overhaul at 500 hours on a 2,000 hour TBO engine is normal. Yes, it is. A top overhaul isn't what is referred to as being part of TBO. TBO refers to a major overhaul. Having to swap cylinders and other components prior to TBO isn't unusual at all.

If one is performing top end work at 500 hours, this doesn't mean that the engine didn't "make" TBO.

It's also worth noting that many engines, when overhauled, have very little done to them. Very often most components stay the same. So long as the component is within tolerances, it may very well remain in the engine indefinitely unless issued a life-limit by the manufacturer (very rare). Therefore, when an engine has just come from a fresh overhaul, it may very well be pretty much the same engine that went in. There is no set standard.

 

[avbug]

Surplus1,

The vast majority of my work on radial engines was with the R-2600, QEC's from B-25's to other aircraft. I also worked with, flew, and maintained the R-2800, R-3350, and R4360. While I have a lot of appreciation for the smoothness and quiet of the 4360, it is a maintenance nightmare. It likes to catch fire a lot, a pinhole leak in a BMEP line can wreak havoc and make it unusable, and a cylinder change on that engine is a b*tch.

The 3350 was probably the most highly developed radial ever built, though my back still hurts when thinking about trying to change out a PRT on that engine.

Yes, I'm flying. I've always worked as a mechanic in conjunction with my flying, until now. Turbine equipment isn't nearly as fun; it seldom breaks, and emergencies seem to be measured in intervals of years rather than minutes. No fun at all.

I was a flight engineer, but not in a grand sense. More for the dabbling and experience, than a job. It's always been about driving, for me. Sitting sideways, while honorable, is only to be endured until being able to drive. Wrench turning, on the other hand, is both a pleasure, and a curse.

(Wrenches don't turn far without sufficient and ample cursing...)

 

[Acestick]

Even if your engine quits in the pattern, it doesn't mean disaster...

A lot of pilots get tunnel vision and focus on the numbers of the desired runway...But they often don't realize that the airfield is also a decent spot to put the plane down in...It has other taxiways and runways, not to mention it is usally at least a square mile of open field with paved surfaces and trimmed grass...Just aim for the airport, and if you make the runway great...If not, then just aim for the airport and chances are you'll survive anyways...

If it ever comes down to a situation where it is me or the airplane, I'm gonna be walking away and watching a crane pick up the rest of the plane...