Prop strike/gearbox check? Questions

[RFSchaller]

In the line maintenance course the instructor demonstrated the crankshaft deformation check. It was pretty simple. He said his shop charges $700 to do the check, but he said the customers never complain when it comes out satisfactory!

[Sink]

Hi Yankee,
If you want to do a complete prop strike inspection by all means go for it. You evidently believe that scuffing a tip didn't cause any damage more than a scuff and you said it wouldn't be an issue in GA aircraft and I agree.


Our manuals for the most part are cut and dry, but not all issues or situations are. They are written for both untrained and trained personnel. This is where 20+ years experience comes to play. The manuals are written as guide lines and not always rule. Certainly some things are hard and fast fact, but some aren't. Untrained tend to go strictly by the manual and trained long time Rotax mechanics use them in many situations as both guidelines and fact. Knowing when to apply what takes years of experience and usually many Rotax classes. There are gray areas and some written for CYA instances. I see many prop strikes per year and if Yankee really only scuffed 1/16" the thickness of a nickel with a light composite prop then he'll be good.
There is no substitute for experience even with the manuals. There are some things in them that are actually wrong and we have been working for a change. That's one reason we have manual revisions that have been going on since the 912 was first produced.

I still stand by the comment that if you think there was enough force to cause damage for a gearbox inspection then there is sufficient evidence to do the entire prop strike protocol. It should be all in and not just part way. Half way is no better than not at all if you believe there was sufficient evidence and damage to warrant a prop strike inspection.


Common sense and experience must be included as nothing is exactly the same as in the manual for many issues. Case in point. RV12's at this point in time and low fuel pressure. The solution isn't in the manuals.

[rvbuilder2002]

Originally Posted by Sink

Common sense and experience must be included as nothing is exactly the same as in the manual for many issues.

I whole heartily agree.

The problem is that anyone with experience, that is giving advice in this thread hasn't actually seen the damage (there haven't even been any photos posted to look at...... So that experience is of little value since the decision is falling back to the OP's judgment of how bad the damage is.

In a case like that, I feel no one is doing him any favors, other than to be conservative.

Once again, all in with the recommended inspection is not much more than removing the gear box....... (it's in the manual)

Originally Posted by Sink

Case in point. RV12's at this point in time and low fuel pressure. The solution isn't in the manuals.

I am not sure what relevance this has to the discussion in this thread.......
In the prop strike instance you are saying don't follow the manual, even though it has a published recommendation.
Here you are quoting a problem that you say isn't in the manual.
?
?
?

[RFSchaller]

I think this discussion is about peace of mind. If anything out of the ordinary happens to my engine I get out the books and see what is required. Then I get the gut wrench over the effort required, and eventually bite the bullet and do it. The only way you will put this to bed is to do the prop strike checks regardless of what a PITA they are.

[KALEWIS]

I'm a little curious to the circumstance around the PS. seems that a gear or tire failure or possibly a hole in the runway surface would cause a minimal strike. If the OP doesn't want to share, that's fine, just curious as to how it happened.

[rvbuilder2002]

I can't say for certain, but my guess would be it is probably THIS

[BigJohn]

Originally Posted by rvbuilder2002

I can't say for certain, but my guess would be it is probably THIS

Probably. But the decription included in that entry " AIRCRAFT LANDED AT GREEN COUNTY AIRPORT, DAYTON AND THE HAND NOSE WHEEL SEPARTED FROM AIRCRAFT, DEPARTED AND, ON LANDING STRUCK THE PROP, MORAINE, OH" is so vague as to be pretty useless. Unless Wayne wants to share more details ( his choice) details of this incident are pretty much pure speculation. The description above makes it sound like the nosewheel is what the prop struck, but that is not what Wayne said in his original post.

Regardless of advice as to "common sense" etc., and not knowing every detail of the incident or damage, I would lean toward the conservative approach, and follow the Rotax procedures as outlined in their manuals. JMHO.

[joedallas]

When something really bad happens it is usually a chain of events.

don't take any chances ( check everything )

Break the chain

My view

Joe dallas

[f1rocket]

Great advice Joe. I totally agree.

[yankee-flyer]

Didn't mean to start a controversy. I'm "going by the book" and gearbox will go off to Lockwood tomorrow. THANKS guys

Wayne