Prop Strike today, October 8, 2013

[yvesg]

Bob, it is hard to judge how deep is the hole from the picture? What do you say it was?

Yves

[RocketAviator]

Bob, I truly feel for you, wish there was something I could say or do to make it easier on you..  As you know I just went through the insurance / away from home shop repair... it was a challenge at a minimum but it was doable!

 

Let us know how it turns out,

[kerry]

I'm sorry for the mishap, but I'm glad You posted it.  A lot of the times I don't stay on the yellow lines.  I'll now pay closer attention when I taxi.

[laytonl]

Bob, I'm sorry to hear about your incident. As you know, I suffered through my partner's gear up last year, so when you get back home, give me a call and I can share more about our experience.

Basically, my partner's gear up was a relatively painless event and I actually feel like the airplane is better than before. Insurance (AOPA) was easy to work with, though we did have to haggle a little about the prop replacement because our prop had not been overhauled in over twenty years. In the end AOPA covered all expenses except for a few hundred dollars of miscellaneous stuff. I really could not have asked for any better service than we received.

I was surprised that the mandatory tear down required overhaul the prop governor, mag overhaul, and vacuum pump replacement. Lycomings list of mandatory replacement items is extensive.

The insurance premium increased slightly, but not significantly.

Lee

[Hector]

That hole did not look too bad from the pictures but that could be deceiving. Now I'm going to be paranoid about every imperfection on the ramp. Sorry this happened to you!

Sent from my iPad using Tapatalk HD

[BigTex]

We have to be super careful taxiing.  This same exact thing happened to Jerry Johnson a couple of months ago where his noise wheel fell into a crack and caused a prop strike.  If it happened to Jerry, it could happen to anyone.

[rc454]

I would not even fly around the patch behind an engine that had not be torn down after a prop strike - unless the airport offered plenty of emergency landing real-estate.

 

Ron A&P, ATP, CFI

[kellym]

Engine is 700 sfrm. I took pictures of the taxiway, pretty dangerous spot, the gal in the office brought out 2 orange cones after the horse left the barn.

 

The shop proposes sending the prop, a 4 year old Scimitar to New England Prop Service in Conn.

 

The engine would go to Unlimited Aero Engines in Fitchburg MA.

Gary, what would one make the call on tearing down the engine on? And with insurance involved should I take a chance?

Anyone know either? The shop on the field was high on both... 

My condolences. There is little choice on engine. There is an AD that requires inspection of the crankshaft gear at the rear of engine, which requires removal of the accessory case to get to. There is also service bulletin from Lycoming. I see you have been already provided with links.I'm not familiar with shops in N.E. as to best for teardown, other than Zeyphrhills in FL is top notch.

Shipping will be similar to any of the shops, unless they are close enough to send a truck to pick it up.

In most cases insurance companies have no problem paying for R&R and teardown. Anything beyond gasket replacement in parts or upgrading is your cost.

You can choose to do nothing with cylinders, or have them cleaned up, inspected and re-ringed. If your compressions were good, I'd be tempted to do nothing besides a valve wobble check. They can remove cylinders without pulling piston all the way out, so rings stay put.

Forget about ferrying the aircraft. Most FSDO's will not approve on a prop strike, even though they should with the AD done and airworthy prop. I know my Aridzona FSDO will not approve. At least plane is within a day's driving distance.

You may want to wait for engine shop report before you decide whether to have enough done to call it an overhaul. Only wear parts like bearings, rings, etc need to be replaced for overhaul, along with any that are unairworthy. You do not have to replace all items in Lycoming 342 service bulletin for Part 91.

Main expenses are having crank, cam and rods inspected. I prefer to concentrate on making items that can only be replaced when case is split. Anything that can be replaced on outside of engine just needs to be airworthy, not necessarily overhauled or new. A field overhaul that only replaces unairworthy items and wear items can be less than 1/2 cost of a full new limits overhaul, but they read the same in logbook. With insurance, your only decisions will be repair/replace prop, inspect and reassemble engine or do minimal overhaul. It will cost down time, but  you wouldn't be able to get a cheaper overhaul to zero SMOH.

[kellym]

Bob, I'm sorry to hear about your incident. As you know, I suffered through my partner's gear up last year, so when you get back home, give me a call and I can share more about our experience.

I was surprised that the mandatory tear down required overhaul the prop governor, mag overhaul, and vacuum pump replacement. Lycomings list of mandatory replacement items is extensive.

The insurance premium increased slightly, but not significantly.

Lee

It is NOT mandatory to overhaul prop governor, mags, vacuum pump for engine overhaul, much less a teardown. The Lycoming service bulletin that calls for such things is merely advisory UNLESS you are flying Part 135 or other commercial operation where the certificate may require adhering to service bulletins. For Part 91 service bulletins are ADVISORY no matter how big the letters are nor how frequent it says mandatory on it. Only ADs are mandatory.

Personally, any honest A&P should offer the option on those items, depending on circumstances. A metal contamination of engine certainly calls for prop governor overhaul and inspect and reseal of prop. But a hangar door hitting prop doesn't justify overhaul or replacement of accessories.

[Alan Fox]

I would bite my tongue about that hole , if the aircraft was taxied on the center line of the taxiway as illustrated by the yellow line , this post would not exist.....We all (myself included) get a little complacent in our routines at times.....performing the service bulletin inspection is actually easy , you don't have to remove the oil pan , you cut the gasket at the case seam , and install the last three inches of it with proseal and it will never leak again , also if you remove the top engine mount bolts , and loosen the bottom engine mount bolts , you can cant the engine forward a few inches which makes removing the accessories and rear case easy.....No ferry permit needed , its done....

[DaV8or]

The hole does not seem that deep although the pictures may not reflect the depth

 

Clearly it's deep enough and now we can all see how this happened and how it could happen to us too. "It doesn't look that bad, I'll just drive right across..."

 

Sucks to hear of your loss, but thanks for sharing Bob! Hopefully, we will all taxi with a little more care with this incident in mind.

[chrisk]

 if the aircraft was taxied on the center line of the taxiway as illustrated by the yellow line , this post would not exist.....We all (myself included) get a little complacent in our routines at times....

I was doing my 3 landings for night currency last night.  It was a nice clear and calm night, but very dark with no moon.   Your exact words were echoing in my head.   "Chris, Taxi on the yellow line!  They put it there for a reason."

[N601RX]

From Bob's view sitting in the pilot seat and looking over nose, you would only be able to see the hole if you were 20-25 ft away.  The fact that is was on the other side of the manhole may have made it more difficult as the manhole cover appears to be raised slightly.

[Bob_Belville]

Not all prop strikes are created equal!

 

Sounds like yours was "significant", but your A&P will have to decide on the degree of inspection/teardown.

 

Here's the AD that defines a prop strike and directs you to the Lycoming service bulletin:

 

http://www.caa.si/fileadmin/user_upload/pageuploads/AD-NOTE/AD-2004/038_FAA_AD_2004-10-14.pdf

 

The Lycoming bulletin is at:

 

http://www.lycoming.com/Portals/0/techpublications/servicebulletins/SB%20475C%20(01-30-2003)/Crankshaft%20Gear%20Modification%20and%20Assembly%20Procedures.pdf

 

Notice that while there is virtually no "wiggle room" on what constitutes a prop strike, other than the replacement of the crank bolt and lockplate, the AD  doesn't address much else.  Changing out the crank bolt does not entail splitting the case, just removing the accessory section and sump of the O-360.

 

I have two acquaintances that had engine failure directly attributable to previous, un-reported "minor" prop strike damage.  It is something to be taken very seriously.  Think about that while flying over W. Virginia on a dark night.

I am 99% convinced to go ahead and have the tear down inspection done. Both tips of the scimitar were chewed up and bent a little. STM engine might have felt more than it would hitting grass or... A couple of guys with Mooneys in Connecticut had very good things to say about New England Prop shop and the engine guy, Tim Hess would used to build engines for Red Bull racing...

[Bob_Belville]

Bob, it is hard to judge how deep is the hole from the picture? What do you say it was?

Yves

The area around the cover was pretty uneven and from where the prop marked the pavement I think I must have dropped into a "hole" beyond the cover that was the lowest, perhaps 10-12" across by 2-3" deep. I don think more than that though as I said the whole area is uneven and the MSL of where the prop hit might be 4 or 5" above the bottom of the whole. Add in a little pitch down when the wheel dropped... I was going quite slow, I knew the whole place is rough. (They're suppose to get the runway paved next year!

[Bob_Belville]

Bob, I'm sorry to hear about your incident. As you know, I suffered through my partner's gear up last year, so when you get back home, give me a call and I can share more about our experience.

Basically, my partner's gear up was a relatively painless event and I actually feel like the airplane is better than before. Insurance (AOPA) was easy to work with, though we did have to haggle a little about the prop replacement because our prop had not been overhauled in over twenty years. In the end AOPA covered all expenses except for a few hundred dollars of miscellaneous stuff. I really could not have asked for any better service than we received.

I was surprised that the mandatory tear down required overhaul the prop governor, mag overhaul, and vacuum pump replacement. Lycomings list of mandatory replacement items is extensive.

The insurance premium increased slightly, but not significantly.

Lee

Lee, thanks for that! I will call, I just got back and filled out the ins report. This is my first year with QBE. We'll see. I will point out the mags/gov/pump to the shop just in case he missed... might as well do it right.

[Bob_Belville]

I would bite my tongue about that hole , if the aircraft was taxied on the center line of the taxiway as illustrated by the yellow line , this post would not exist.....We all (myself included) get a little complacent in our routines at times.....performing the service bulletin inspection is actually easy , you don't have to remove the oil pan , you cut the gasket at the case seam , and install the last three inches of it with proseal and it will never leak again , also if you remove the top engine mount bolts , and loosen the bottom engine mount bolts , you can cant the engine forward a few inches which makes removing the accessories and rear case easy.....No ferry permit needed , its done....

I can beat myself up pretty well but thanks for piling on.  In my defense, and I'm not making excuse, from where I was tied down I had to taxi across about 30' of unmarked "ramp" to get to the taxiway line. That's where I hit the hole. Obviously I could have taken a safer route...

[Bob_Belville]

Guys, thanks for all the empathy, kind words and advice, much appreciated! I'll probably feel moved to keep you all posted on progress. And if anyone has an extra seat flying from this general area to that general area for a day or several... I would not mind being able to drop in to Stow or KFIT and make a pest of myself.

[Alan Fox]

I can beat myself up pretty well but thanks for piling on.  In my defense, and I'm not making excuse, from where I was tied down I had to taxi across about 30' of unmarked "ramp" to get to the taxiway line. That's where I hit the hole. Obviously I could have taken a safer route...

I am in no way trying to assess blame or guilt or anything like that , (which is why I included myself in the statement) my point was that we are all guilty of complacency and need to be more rigid in our practices......Thank you for sharing this as I'm sure it was not your proudest moment , BUT it may preclude someone else from doing the same thing....... 

[Bob_Belville]

Ouch.

[Cody Stallings]

I belive I could fix those blades if the bearing shelf is not cracked.........the problem with that propeller is going to be the Hub. Heartzell makes a great propeller, however the hubs don't standup to much impact.

[fantom]

I belive I could fix those blades if the bearing shelf is not cracked.........the problem with that propeller is going to be the Hub. Heartzell makes a great propeller, however the hubs don't standup to much impact.

 Cut down the tips, file the rough edges, paint, rebalance and new hub.....?

[Bob_Belville]

When I installed the PowerFlow Exhaust I had the prop harmonically balanced. Doubled the PFS warranty. Would shortened, repaired blades be any balance issue?

[Cody Stallings]

That's just what the Hartzell manual calls for. Reduce the diameter to remove damage...... Cutting the dia back will not affect the dynamic balance, cause both blades will bet the same in as far as length, angle, edge height, ect. As long as the damage could be removed without going below the minimum dia. Permitted on the TC data sheet...... After reading the posts about a very low power setting when this happened, it's possible the hub may have survived. If so, that's $3500 saved

[Bob_Belville]

That's just what the Hartzell manual calls for. Reduce the diameter to remove damage...... Cutting the dia back will not affect the dynamic balance, cause both blades will bet the same in as far as length, angle, edge height, ect. As long as the damage could be removed without going below the minimum dia. Permitted on the TC data sheet...... After reading the posts about a very low power setting when this happened, it's possible the hub may have survived. If so, that's $3500 saved

I suppose even -1/2" or so of tip would round off to zero change in performance?