Warbird Information Exchange

HI IVE COMPLETED FOUR T-6 A.D. INSPECTIONS AND DID NOT FIND ANY CRACKS,WHAT WILL BE THE BOTTOM LINE AFTER ALL THE INFO IS IN?HAS ANY ONE FOUND ANY CRACKS?ITS MY OPINION THAT THE FIGHTER PILOT IN A DAY SCHOOLS HAVE SUCEEDED IN GROUNDING ALL OF THE T-34 ARE WE GOING TO LET THAT HAPPEN TO THE T-6 FLEET AS WELL?AS A OWNER OPERATOR YOU NEED TO VOICE YOUR OPINIONS ON THIS TYPE OF OPERATION BEFORE WE END UP WITH A WHOLE LOT MORE LAWN ORNIMENTS/WIND INDICATORS .THANKS MIKE

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IF YOU CAN FIND IT WE CAN FIX IT

I cant speak for Top Gun or any of the other T-6 flight operators, but we are not doing any aerial combat flights. Orientation flight with light manuevers and T-6 check out flights are all that we are doing.
I would agree that we need to do what it takes so that an accident like this doesnt happen again.

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Live to fly, Fly to live.....

I know of 22 planes checked and no cracks.

I talk to a few guys in the CAF, and other T-6 operators, and it's pretty unanimous; this was an isolated incident. Most seem to feel, that the emergency AD will fade away after some time.

Did WA ever do any ACM flights with the aircraft in question?

Does anyone know the result of the metallurgical report of the failed attach angle? Can someone send me a copy?

Hi All,

If I may....I have not been following the thread very much on the attach angle issue. But if I am correct in assuming that you are to use Flourescent Penatrent on this please be aware of the following factors. Exfoliation corrosion can and does lead to cracking. While you may not have seen any evidence of cracking on the surface, please be aware that while no surface indications appear, there may be something below what you can see. Believe me, I have "been there done that" in some aircraft I have inspected. If you suspect ANY problems, no matter how small, look for distress in the fasteners and the surrounding area.

I apologise if this is abit alarmist, but I do tend to err on the side of caution in my inspection.

Respectfully,

Paul

Hi Paul:

The exfoliation I've seen tends to leave a bump on the surface, because of the internal corrosion cell. Also, I've noticed while tapping the metal, exfoliation will leave a dull "thumpping" noise.

Hi Paul,
very well said. This type of corrosion will end up in a failure if left undetected. There is absolutely no possible solution but change the parts. Structure repair manual for Harvard will not allow any repairs in regards to this corrosion. It will keep going as a cancer and the part WILL FAIL.
During inspection for the Emergency AD there was no sign of corrosion until last application of stripper. It looked like a blistering paint and upon close look there it was. It only took a fingernail to break off a large piece. Both sides of rear lower attach angle are affected.
My aircraft is 1952 Harvard Mark IV which I've owned for 28 years. It is one of the last serial numbers manufactured and has been used in Airshow flying for 25 years.
I for one am grateful for this AD.
Below are the two pictures of the affected areas.

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The attach angles are being changed as we speak.

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Regards

John

John,

Thank you for posting the photo's and helping me with a visual "proof of point". Exfoliation or as it also is sometimes called "Inter Granular Corrosion" hides it's presence very well. As evidenced by your photo's . Thank you for sharing them here.

Respectfully,

Paul

Also,

Well put. The tapping, while perhaps not an "approved" method for corrosion detection, does lend itself to aiding you in finding "dead spots" or more properly termed, delamination, of the aluminum at the grain boundary level of the metals structure. A dead spot will sound hollow or dull. But by no means should that be used as a guideline for corrosion detection. If an AD is issued...follow it to the absolute letter.

Respectfully,

Paul