A good day ends badly in El Paso

[jcovington]

On December 22nd my wife and I planned a trip to Tucson to spend Christmas with our family. We had planned to leave on Friday the 21st but icing conditions in Huntsville made us push the trip from Friday to Saturday. Saturday was a beautiful day to fly with clear skies and good visibility. The headwinds were high but that isn't unusual this time of year. 

We wanted to get to El Paso by about 4:00 PM so that we could make Tucson before it got too dark. Everything was working great as I called for clearance from El Paso ground and taxied out to 26L for takeoff. After receiving our takeoff clearance I leaned for the high altitude and started the takeoff roll. A few seconds after rotation I heard a fairly loud thump and felt a shutter in the airframe. I scanned the engine instruments and everything looked good. The plane was flying fine. My first thought was that the airliner that landed just before us lost some tire tread or we lost some tread from the right tire. I called the tower and reported the noise and that I though I had hit something on the runway. I stated that I wanted to return to land and check for any damage. The tower cleared me for a downwind and reported that our gear looked fine.  He also stated that he didn't see anything on the runway. I left the gear down, did a normal downwind and eased the plane onto the runway. Even though the tower stated that we had no damage I wanted to be careful. 

We parked back at Atlantic and I checked the plane over. I started at the right wing since I though I had hit something with the tire. I couldn't find anything on the wings or the belly. One of the Atlantic guys asked if I had always had scratches on the prop. When I examined the prop I knew we were done for the day. One blade had scratches across the entire backside of the blade. There were also a few scratches on the front side but nothing like the scratches on the back. What is really disturbing is that you can move the blade several inches fore and aft. The blade also rotates about 10 degrees without any resistance. After seeing the damage I felt good about the decision to land and check the plane. 

I called Joey Cole at home (what a guy to take my call on a holiday weekend) and he wanted pictures to see the damage. He though I might have had a prop strike requiring an engine teardown. When he saw the pictures he believes that the hub has failed and there was no prop strike. 

I had called the tower after finding the prop damage and suggested they check for FOD on the runway. They weren't able to find any FOD but i am fairly certain that at least some of our prop hub was left on the runway. So far I have spoken with the tower, operations and the FSDO. It looks like they will be classifying the event as an incident and not an accident. We'll see how that all plays out. I am to follow up with the FSDO manager when we determine what happened.

The good news nobody got hurt. The plane will be fixed. My wallet may be a bit lighter when it is finished. 

Tomorrow we are driving to Tucson. Before I do that Joey wants me to remove the spinner and send him pictures. I'll update the thread when I see the hub.

I'll post prop pictures shortly.

Jim
 

[carusoam]

Jim,

Great decision making!

Thanks for sharing the report...

Can you post the pics?

MS has a prop guy that may have some experience with this...

@Cody Stallings

Do you know what prop you have? In case a hub or blade can be made available to get you back in the air?

Good luck with your next steps.

Best regards,

-a-

[jcovington]

Pictures of the prop blade damage. 

Jim

[jcovington]

14 minutes ago, carusoam said:

Jim,

Great decision making!

Thanks for sharing the report...

Can you post the pics?

MS has a prop guy that may have some experience with this...

@Cody Stallings

Do you know what prop you have? In case a hub or blade can be made available to get you back in the air?

Good luck with your next steps.

Best regards,

-a-

I do not know the part number of the hub. I'll see if I can get a part number when I pull the spinner tomorrow. 

I would be very interested in Cody's comments. Joey says he has never seen this type of failure. 

Jim

Edited December 23, 2018 by jcovington
Typos

[FloridaMan]

Prop AD in 3...2...

[carusoam]

Looks like something may have left via inside the spinner...?

The spinner got pressed enough to take the paint off in that area... with a close scratch on the blade...

Probably see a lot better with the spinner removed...

 

Cody has some contact numbers and an email posted in public view on his website...

https://www.stallingsaircraftpropeller.com/contact

 

Also leaving an invite for the Doc... @M20Doc

As usual, i’m Only a PP, not a mechanic...

Best regards,

-a-

 

 

[RLCarter]

the damage is only on one blade or both?

Edited December 23, 2018 by RLCarter

[GDGR]

I’m trying to get my head wrapped around how something going 3000 RPM coid cause damage perpendicular to the rotation? 

Something appears to have been wrapped around the prop,IMO. 

Glad you’re safe, and anxious to hear what you find. 

[xcrmckenna]

I’m trying to get my head wrapped around how something going 3000 RPM coid cause damage perpendicular to the rotation? 
Something appears to have been wrapped around the prop,IMO. 
Glad you’re safe, and anxious to hear what you find. 

There is a snap ring right at the base of the blade. If that came lose and slid down the blade as it was spinning could explain the perpendicular marks?


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[jaylw314]

40 minutes ago, xcrmckenna said:

There is a snap ring right at the base of the blade. If that came lose and slid down the blade as it was spinning could explain the perpendicular marks?


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I imagine that would scratch the leading and trailing edges, but the face of the blade??  What the heck is going on?

Glad everyone is back on the ground safely, though!

[Niko182]

Good thing you went back. Last i checked losing a blade mid air is nearly always fatal

 

[Mark89114]

Aren’t there some counterweights and keeper in there somewhere?  That coming loose would explain blade being that loose.  Glad you are OK.

[Guest]

First thing, good decision on returning and glad that you’re both fine.  

I would guess that the blade snap ring failed and slid down the blade causing the damage.  Once it’s gone and the engine is stopped the blade will be free to flop around in the hub.

Here is a picture, I’ve marked the snap ring.  It may not be your exact prop, but the design is similar.

Clarence

Edited December 23, 2018 by M20Doc

[ArtVandelay]

When is the last time the prop was serviced (resealed or overhauled)? Is the plane hangared? Because I would guess corrosion of some kind is the cause.

Can someone elaborate on what kind of inspection is done during the annual? I assume as least the spinner is removed and the prop greased.

[Guest]

2 hours ago, Niko182 said:

Good thing you went back. Last i checked losing a blade mid air is nearly always fatal

 

In this case the blade won’t leave home due to the design.  The snap ring only holds the blade shims in place.  Under load there is something like 20,000-40,000 pounds of centrifugal force seating the blade against the bearings in the hub.

Clarence

[LANCECASPER]

Your post should be re-titled, "A bad day ends well in El Paso". Think about if that loud noise had happened as it was getting dark over the mountains between El Paso and Tucson. Your good decision making means you get to figure out all of this on the ground with the expertise of some on here. And the drive from El Paso to Tucson is not so bad.

[Bob_Belville]

Wow. Thanks for posting. There seems to be no end to our education! Great job thinking safety first.


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[jcovington]

First, let me say you guys blow me away. I don't know where else I could get such expert help and on a holiday weekend. I really appreciate it. 

The prop is original to the plane so about 2200 hours total service. About two years ago Joey noticed some leaking grease during an oil change. At annual in February 2017 the prop was removed and sent for a reseal. During annual in February 2018 the prop was again leaking so once again it was removed and the seals redone. That makes it less than a year since the last visit to the prop shop with the plane always hangered. It seems unlikely that corrosion was a factor but still something to check. 

The damage to the prop is only one blade. The other blade shows some wear but we fly the plane about two hundred hours in a year through lots of weather. The wear isn't more than I would expect. The snap ring coming loose makes perfect sense and I believe would account for the damage to the blade. 

After breakfast this morning I will go back to the airport and remove the spinner. More pictures and information to follow. 

Jim

Edited December 23, 2018 by jcovington
Corrected annual dates.

[mike_elliott]

Great decision making Jim. We talk of the need to "complete the mission" being a difficult force to overcome when sometimes the data or situation says to do otherwise. This is a great example of not letting your immediate indications (I scanned the engine instruments and everything looked good. The plane was flying fine) justify rationalizing that everything was good and to continue on to Tuscon. 

Alice and I are delighted you and Teresa are fine. You needed some prop work anyway :)

 

[Culver LFA]

I'm not a propeller expert by any means but with that reseal history I wonder if there was a problem with the hub causing the repetitive leaks and the shop just kept replacing the seal and not finding the actual root cause (I would expect that the shims are reusable but question if the snap ring is one time use or not. Was this snap ring reused each time the prop was serviced and possibly stretched causing this failure?

I just had my prop serviced, I think I'll check the bill to see what parts were replaced...

This will definitely be a learning experience, thanks for sharing!

[LANCECASPER]

30 minutes ago, jcovington said:

During annual in February 2017 the prop was again leaking so once again it was removed and the seals redone. That makes it less than a year since the last visit to the prop shop with the plane always hangered. It seems unlikely that corrosion was a factor but still something to check. 

It looks like almost two years, not that that's a lot better..

[jcovington]

3 minutes ago, mike_elliott said:

Great decision making Jim. We talk of the need to "complete the mission" being a difficult force to overcome when sometimes the data or situation says to do otherwise

Thanks for that Mike. It was interesting as I was debriefing over a couple of beers last night trying to determine what made me turn around. My first inclination was to keep going but something about the noise told me the plane needed to be checked. I still am not sure what. I can tell you I had no hesitation in making the call in spite of knowing I probably wouldn't make Tucson last night. Interesting the way our brains work. 

I sure hope Santa can find me when he brings my new prop for Christmas

[jcovington]

4 minutes ago, LANCECASPER said:

It looks like almost two years, not that that's a lot better..

Opps. It really is only one year since the last service. I got the dates wrong in my original post. I have corrected the annual dates in the post. 

[jcovington]

10 minutes ago, Culver LFA said:

reseal history I wonder if there was a problem with the hub causing the repetitive leaks and the shop just kept replacing the seal and not finding the actual root cause

I have wondered the same thing. The good part of this whole thing is that it will be a different prop shop servicing the prop if it can even be reused. My wife is all about replacing the prop at this point. She may be right. 

Jim

[jcovington]

 

The prop snap ring is gone. Some impact damage to the spinner. I plan to talk to the local maintenance guys about pulling the prop this week. I'll let you know how it goes. 

Wonderful diagnostic effort with just a few pictures. Thanks guys. 

Jim