C210 wing spar failure in Aus : C177 inspection recommended as well

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C210 wing spar failure in Aus : C177 inspection recommended as well

Unread post by Ugly Duckling » Fri Jun 07, 2019 7:45 am

Survey aircraft wing spar carry through failure.
https://www.atsb.gov.au/publications/in ... -2019-026/
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Re: C210 wing spar failure in Aus

Unread post by Iceberg » Fri Jun 07, 2019 7:55 am

A concise report only two weeks after the accident - I wish we could have reports like that.

The fracture is a textbook fatigue fracture. Fatigue fractures occur when there are a high number of stress cycles up to the fatigue stress limit. Below a certain limit, no fatigue occurs, but as the limit is raised, the number of stress cycles required reduces.

The fatigue limit can be much lower than the yield limit. The aircraft had 12700 hours on it - so fatigue is very likely, especially if it flew in turbulent conditions at high speed for long periods. Strange that X-ray inspections did not pick up the crack. I am sure that they must have regular X-rays after a certain age/number of hours as we have.
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Re: C210 wing spar failure in Aus

Unread post by TxT » Fri Jun 07, 2019 8:13 am

Some questions for the experienced C210 operators:

1. Are there any other instances of fatigue induced carry through spar failure on the C210?
2. Is there an AD or mandatory service bulletin in place detailing periodic compulsory inspections of the spar?
3. Is there an AD or mandatory service bulletin in place requiring a modification of the affected section? ( If I recall correctly there was spar fatigue problems on the Cessna twin series aircraft which was addressed with an AD. Also the older Baron series aircraft had an MSB (AD?) issued to address carry through spar web cracking.)

Let's hope that this accident does not spark off an overreaction by the regulators.
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Re: C210 wing spar failure in Aus

Unread post by Ugly Duckling » Fri Jun 07, 2019 8:39 am

The tip tanks may be a factor especially as they operate at 200' at close to gross.

Report mentions a non standard engine and propeller installation. Possibly an unexplored harmonic combination.
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Re: C210 wing spar failure in Aus

Unread post by TOFFS » Sat Jun 08, 2019 1:12 pm

The engine and propeller difference to the manufacturers design isn’t uncommon. This would, more than likely, have been the 550/Scimitar blade STCs so would be very unlikely to be the cause of the spar failure.

Go back to 2013 in regards to Cessna’s Supplementary Inspection Documents (SIDS) and how many of you contributed to the bemoaning on why you, as Cessna owners in South Africa, would have to comply with this and why most parts of the world, including Australia, you didn’t have to. I recall even the local branch of AOPA trying to have this made as recommendation only.

Within the Cessna 210 SIDs are several NDT/fatigue/corrosion inspections that have to be carried out on the main spar carry through. All of these SID inspections are repetitive, and off the top of my head, I think this particular one is at 2000 hour intervals. On a quick calculation, this aircraft’s through-spar would have, if enforced, had at least 3 repetitive inspections.

Cessna owners in South Africa are still complaining of the non-necessity and expense of this scheduled inspection.

The wing tip conversion with extra fuel tanks work by having to fly on your normal tanks until enough fuel is voided to then transfer the wing tip fuel into the standard tanks. This aircraft, according to the report, flew twice a day, full fuel. Flying at those altitudes, bumping along in potholes with that weight and fulcrum every day could not have helped.

As stated previously, the Australian Authorities are very sharp with reports like this. They also have a fantastic system on the engineering side where reports on defects, failures etc, if followed, can show trends in similar type aircraft. SA CAA is supposed have a similar system but it doesn’t work and there is never any feedback or cross referencing.

Remember, these aircraft are getting old and are needing a lot more TLC. It used to take me way longer than the 68 hours recommended by Cessna to do an SID on a 210 correctly. If yours was done in a very much shorter period, the next time you are sitting in your seat cast a quizzical eye just above your head to where the through spar passes!

Carry through spar Cessna 172 found during an SID:
IMG_1395.jpg
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Re: C210 wing spar failure in Aus

Unread post by Ugly Duckling » Sat Jun 08, 2019 1:16 pm

Thanks Eric
Informative and helpful post =D>
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Re: C210 wing spar failure in Aus

Unread post by GL » Sat Jun 08, 2019 2:00 pm

Interesting C172 pic Toffs - and correct me if I'm wrong but C172 spars don't really have much in carry through loads due to the struts.
AFAIK the reason Cessna could/would not put the C210 back into production was because there was no backup in the case of a spar failure like this?
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Re: C210 wing spar failure in Aus

Unread post by Corvus » Sat Jun 08, 2019 11:05 pm

Cessna Wing Spar Test Pic
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Re: C210 wing spar failure in Aus

Unread post by Ugly Duckling » Sat Jun 08, 2019 11:11 pm

And the Luscombe, with struts, seats 28.
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Re: C210 wing spar failure in Aus

Unread post by TxT » Sat Jun 08, 2019 11:55 pm

TOFFS wrote:
Sat Jun 08, 2019 1:12 pm
The engine and propeller difference to the manufacturers design isn’t uncommon. This would, more than likely, have been the 550/Scimitar blade STCs so would be very unlikely to be the cause of the spar failure.

Go back to 2013 in regards to Cessna’s Supplementary Inspection Documents (SIDS) and how many of you contributed to the bemoaning on why you, as Cessna owners in South Africa, would have to comply with this and why most parts of the world, including Australia, you didn’t have to. I recall even the local branch of AOPA trying to have this made as recommendation only.

Within the Cessna 210 SIDs are several NDT/fatigue/corrosion inspections that have to be carried out on the main spar carry through. All of these SID inspections are repetitive, and off the top of my head, I think this particular one is at 2000 hour intervals. On a quick calculation, this aircraft’s through-spar would have, if enforced, had at least 3 repetitive inspections.

Cessna owners in South Africa are still complaining of the non-necessity and expense of this scheduled inspection.

The wing tip conversion with extra fuel tanks work by having to fly on your normal tanks until enough fuel is voided to then transfer the wing tip fuel into the standard tanks. This aircraft, according to the report, flew twice a day, full fuel. Flying at those altitudes, bumping along in potholes with that weight and fulcrum every day could not have helped.

As stated previously, the Australian Authorities are very sharp with reports like this. They also have a fantastic system on the engineering side where reports on defects, failures etc, if followed, can show trends in similar type aircraft. SA CAA is supposed have a similar system but it doesn’t work and there is never any feedback or cross referencing.

Remember, these aircraft are getting old and are needing a lot more TLC. It used to take me way longer than the 68 hours recommended by Cessna to do an SID on a 210 correctly. If yours was done in a very much shorter period, the next time you are sitting in your seat cast a quizzical eye just above your head to where the through spar passes!

Carry through spar Cessna 172 found during an SID:
IMG_1395.jpg

The part in bold in your post could have ramifications wrt this accident. Let's hope the SID's were carried out.

Trawling the NTSB accident database I have been unable to find any C210 accidents caused by carry-through (thru?) spar failure. The number of potential failures prevented by preventative maintenance would be unknown. If data of the number of replacement carry-through spars supplied over the years were available from Cessna it could be telling. (I am presuming that a repair to an existing spar is not permissible.)

It would be interesting to establish what the design life of the carry-through spar is and the operating assumptions made in determining this value.
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Re: C210 wing spar failure in Aus

Unread post by Lood » Sun Jun 09, 2019 6:47 am

Mooney:
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Re: C210 wing spar failure in Aus

Unread post by Bearcat » Sun Jun 09, 2019 6:58 am

Lood wrote:
Sun Jun 09, 2019 6:47 am
Mooney:
Was the Mooney still usable after that :wink:
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Re: C210 wing spar failure in Aus

Unread post by TOFFS » Sun Jun 09, 2019 11:18 am

GL wrote:
Sat Jun 08, 2019 2:00 pm
Interesting C172 pic Toffs - and correct me if I'm wrong but C172 spars don't really have much in carry through loads due to the struts.
AFAIK the reason Cessna could/would not put the C210 back into production was because there was no backup in the case of a spar failure like this?
Guy, load relief by semi cantilever wings (wings with lift struts) versus full cantilever wings can definitely be seen by the use of a top-hat section carry through versus the massive castings of C210s and C177s.

I don’t know Cessna's decision making but think their selection of aircraft to be produced after the court’s ruling on litigation on aircraft over 17 years old had a lot to do with build costs and the eye watering prices they would have had to have charged for aircraft like the 210.
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Re: C210 wing spar failure in Aus

Unread post by JCA » Sun Jun 09, 2019 7:57 pm

Except load tests on wings are usually done upside down!
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Re: C210 wing spar failure in Aus

Unread post by CarlGrobler58 » Wed Jun 26, 2019 8:57 pm

Any idea as to how much that spar will cost to replace?

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