Repairs to primary control surfaces

[Ringway Flyer]

Is it permissible to repair primary control surfaces? At what point would replacement be the only solution? Some club aircraft I have flown have had small patches riveted on, usually to the trailing edge of, for example, an aileron. Is this acceptable practice? (I'm talking metal skinned aircraft, not fabric).

[jxk]

Depends to a degree on the aircraft type: Cessna have a fairly comprehensive SRM (Service Repair Manual) as do other types. If there isn't a scheme available engineering may have to rely on the American standard AC43-13.
That in turn is affected by whether the aircraft in question is a Annex 2 or EASA maintained type and the maintenance organisation has authority to carry out complex tasks. Sometimes it's just easier to fit new component and that depends on whether one is available and at what cost.
Ho Hum!

[Karl Bamforth]

Should also be done by a reputable engineer, don't just pop rivet a patch on. Its not that simple. It requires rebalancing of the flight control.:ok:

[Rod1]

“Should also be done by a reputable engineer”

Really? On an Annex 2 aircraft?:E

Rod1

[Fitter2]

To a degree I agree with KB; noting that 'reputable' and 'licenced' are not interchangeable.

[SNS3Guppy]

Control surface repair is critical. On many aircraft, even repainting the control surfaces requires a full rebalancing of the surfaces. Improper balance can easily result in flutter at subthreshold speeds, or speeds inside the certificated envelope for the airplane.

No repairs can be performed to control surfaces unless specifically authorized by the aircraft structural repair manual, per the aircraft manufacturer.

[hatzflyer]

Unless the "repair" consists of substitution in which case it is no longer a repair.

[Ringway Flyer]

I must make it clear that I've no intention of doing any repairs! I just wondered about the various aircraft that I've flown where such repairs appear to have been carried out.

So either they shouldn't have been done at all, and the damaged surface should have been replaced, or they've been done with the approval of the manufacturer, and should be logged somewhere.

If an unapproved repair had been carried out, would it then fail it's annual/ARC? Would the person carrying out the checks be able to tell if the repair was OK or not?

Logically (I hope) if the aircraft is available and the documents are in order, it should be ok...

[englishal]

Many light aeroplanes have repairs done in the fashion you describe so I shouldn't worry too much.

[A and C]

JXK Offers the best and most accurate advice.

[Pilot DAR]

Repairs to aircraft are really not something pilots should generally worry about UNLESS the pilot is questioning the airworthiness of the aircraft. If you as the pilot are questioning the airworthiness of the aircraft on the whole, or the quality or airworthiness of a repair, you present your concern to the appropriate maintenance person. You do this either before you fly the aircraft, or first thing when you land from the flight where the suspected defect was detected. Present your observation as though you are genuinely willing to learn, rather than calling the maintainer's pride and joy of airworthiness defective!

It is very common for a pilot to pick up on something which is not airworthy, and requires maintenance, or corrective maintenance. It is also common though, for a pilot to question the condition of an aircraft, when it is in fact airworthy. Some factory approved, or otherwise approved and well executed repairs can be rather unusual looking, often for good reason.

Maintenace people are generally patient with pilots who would like to learn more about the mainenance side of things, though questioning the airworthiness of an aircraft may not be the best way to engage these people! Diplomacy is vital in this effort.

In the mean time, the foregoing posts offer good collective wisdom on control surface repair. There can be more to it than meets the eye.

Pilot DAR