PDA

View Full Version : Cessna SIDs: which models hardest hit?


rubberprune
8th Mar 2016, 09:48
As a GA pilot interested in owning a Cessna, I would love to hear from LAMEs (and others) who have carried out initial and/or recurring inspections and are seeing patterns of damage or corrosion that appear more on some models than others.

Is it a proven assumption that older models ('50s and '60s) are the hardest hit?
Are there some other models and years for which Cessna have specified the least number of supplemental inspections due, perhaps, to a 'better design' amongst Cessnas? For example, looking at SIDs for pre-1968 100 series models on the Textron website, it appears to me that the C150 has a significantly larger number of critical inspections, while the C182 'gets off lightly'.

I'd love to hear your thoughts.
: )

NutLoose
8th Mar 2016, 11:56
I have carried out the SIDS on several 152's and the only real corrosion issues I have found personally was behind the wing cabin air intakes where moisture had got in.
You have to remember a low houred aircraft is not always the best as it may well have been sitting in long grass outside etc and any moisture build up will not have had a good airflow through the aircraft to get rid of it, which a regular flyer would have, same goes for the engine, an engine needs to be operated at regular intervals to ensure a good coating of oil on the internal surfaces and again to dispel moisture out of the oil, ground running incidentally may not achieve the latter as it never gets fully up to operating temperatures.
Sids like the wing attachment will need the wing mounting bolts pulling for NDT inspections of the holes, I as a matter of course replace the stiff nuts and bolts with new when doing this, it makes sense as they could have been in there for years.
But our aircraft are regular flyers and they get the maintenance they need, items like the aileron control hinges have all been changed over to the later pin design, you will have to factor in the costs of items you may need, generally Cessna parts are not badly priced, but they do have some that for some strange reason appear to be priced at space shuttle costs.. the piano hinge for the elevator trim tab on a 152 will cost north of £1000.

Fly4Business
10th Mar 2016, 12:51
From what I see and hear around, the dominant part in findings related to the SID are the once related to care, not model. Some parts do stand out, such as the notorious problem with the engine mount in 152s or the gear U-bolts in pre-1968 172s, but besides from these already before SID known issues, I do not see any real surprises. The 150/152/172/182 are quite easy to be SID'ed, while the worst I heard is pressurized 210s. Don't let yourself be fooled by the pure number of listed items in the SID, work is not really related to that bare number.

rubberprune
11th Mar 2016, 09:49
Thank you Gents for your replies.
I have also heard from a LAME that the quality of some early Cessna's alloy appears to be superior in some way that in his experience he's noticed less (and sometimes no) corrosion in those early models when compared with 70s and 80s examples. It was a "they don't build 'em like they used to" remark.

I wonder if others of you feel this way too.

Engineer_aus
14th Mar 2016, 05:05
The ones that I have seen all depended on how they have been looked after and how they have been flown. There is a huge amount of variables which really you can't point your finger on. Some models have cracks, others have corrosion.

ericferret
15th Mar 2016, 12:33
The Reims built aircraft had corrosion proofing at build. Ours is now pushing 50 with zero corrosion internally. Externally it's another matter. That is not the aircrafts fault but the product of a maritime climate, outside storage and worn out surface protection (paint!!).
Nowadays hangared and hopefully a few years left in it. 50 years is not bad for a disposible aeroplane.

Fly4Business
16th Mar 2016, 14:52
While the Reims Cessna had standard corrosion treatment, what in the US was a paid upgrade, it is not a full protection.

Two things have to be remembered.
First, the Zinc Chromate corrosion proofing at Reims was applied after the frames were riveted. As plates do move slightly, edge corrosion may be an issue at Reims Cessnas and that is not easy to identify.
Second, only extremity got treatment, the central cell got no corrosion proofing at Reims. If you take off the side panels in the center cell and you see greenish paint, it has been worked on before.

NutLoose
16th Mar 2016, 20:32
Yep, the new Pipers are not that great either, we have a "corrosion proofed" newish pa28 warrior 111 and one whole rear fuselage side skin has no internal paint, additionally when we had to repair a wing following a ground incident we found that while the skins had been painted externally when disassembled there was no paint under all of the skin joints, and that is where the corrosion forms as moisture / water wicks along them.