Wednesday, October 31, 2007

2007 Annual Inspection

Hard to believe that a year has past since the "Dreaded Annual" we completed last September. This year's annual was scheduled for the first week in October, which is why I haven't posted much to the blog lately. 36G's been in annual and I've been traveling via the airlines for work.

NOTE: I like waiting until close to the last day of the month to drop off the plane, so the sign-off is in the following month. Annuals are due at the end of the month, so this trick is a way to gain an extra few weeks out of the deal.

The Agenda
The plan this year is to keep pushing the bar toward 36G's extreme makeover. What I'm trying to do is to pick off all of the airframe projects, so we can get her into the paint shop -- hopefully this winter.

My Squawk list this year was mostly maintenance items that I haven't had time or facilities to complete such as changing the cam-loc fasters on the cowl, replacing the magneto/spark plug harness, replacing the air induction tube boot, etc. However, I also have a big one on the list...pulling the landing gear and power coating it.

Removing the landing gear?
If a Mooney hasn't been maintained by a Mooney Service Center throughout its life, then it is very likely that at some point the gear was not rigged correctly. Mechanics that don't rig Mooney gear regularly should never touch it -- PERIOD! It is a complex and tricky setup that only qualified mechanics with recent experience (no less than 4 Mooney Annuals a month) should rig.

36G was owned by a bank president before me and had been maintained well; however, the maintenance was not performed by a Service Center. Not by choice...the previous owner simply did not have a Mooney Service Center close to Kansas City where 36G was based.

I've always had concerns in the back of my mind about 36G's gear. Nothing specific. Just something that has kept eating at me every time I move the gear lever. I've personally inspected the gear and numerous qualified IA's before me have as well. We could never find anything wrong, but I've learned early in my career that not finding anything doesn't mean there isn't anything to find. I've also learned over time that my instincts are generally accurate. If I have a concern about something, I need to turn over every stone until I unearth it or rule it out.

I suppose most people would have been happy with not finding anything wrong, but I'm not most people. I want 36G to be perfect and quite probably the best Mooney anywhere. 36G can't be the best if she isn't the best from the inside out. So this year I decided to replace all of the landing gear bushings, hardware and strip, inspect and powder coat the gear.

I know this may be a bit extreme for most owners -- especially considering this is typically a 10,000 hour maintenance item and virtually unheard of on a 700 hour airplane! However, my perspective on this is that it is like buying gear up landing insurance. I want the peace of mind to know that the gear is rigged right. And I most certainly don't want to go through the cost and downtime of a high-end paint job only to have it destroyed by a gear collapse some day.

The findings
To all of our surprise, we found a torsion bar that was slightly bent. It was hardly noticeable until it was rolled over a flat surface, but it was deformed enough to potentially cause a gear collapse in a high speed left turn. WOW!

NOTE: Let's not forget that the gear worked fine, the tensions all checked perfectly and there were no obvious issues, yet one of the primary tension bars were bent! Preventative maintenance is the key. We would have never found this if it weren't for pulling everything apart and inspecting each component individually.

By the way, our speculation on what happened to the torque bar is that a previous mechanic put too much tension on it when adjusting the gear. This is a typical mistake because the gear is a pain to rig. Mechanics often think a bit more tension is better than not enough. Not so with the Mooney. It must be exactly right and there are a number of NTSB reports that substantiate this claim.

The moral of this story is take your Mooney to someone that knows what they are doing!

Conclusion
As Coy Jacob says, To put a fine point on it...The Mooney is a steel and aluminum airplane that can literally live well beyond mere mortals like us. However, it will only live a long life if it is maintained properly. What does maintained properly mean? Know your plane and stay on top of every little thing. Fix it as you go and don't let anything slide that may bug you. If it isn't right or you have concerns, fix it! Your life, your family's life and countless people on the ground are depending on you to make the right choice. And if that is not good enough...do it for your wallet. Well maintained airplanes command top dollar on the resale market and unscheduled maintenance costs are considerably less for owners that perform routine preventative maintenance. If you choose to own a plane, then make the choice to make it immortal and valuable to others -- maintain it properly!

1 comment:

Chris said...

Great site you have here, full of tons of useful and interesting information. Very interesting find with the landing gear there, and I absolutely admire your commitment to nothing but the best. After all, if you're going to give so much time and energy to something, it's certainly worth doing to the best of your abilities. Keep up the good work!