When is a Specialized AMO Needed?
The answer may surprise you
By Brian Whitehead
Regarding the Canadian Aviation Regulations, people often ask what is involved in bringing a small piston-powered aircraft into commercial air service, if the last engine overhaul was done by a freelance AME and not by an engine AMO?
The questioners are usually surprised to hear that there is no need to have the work repeated by a specialist organization. The reason for this apparent contradiction is that there are two distinct kinds of Approved Maintenance Organizations (AMO), and each has a different purpose. I have touched on the AMO rating system before in this column, but as the system is unique to Canada, and still new to some readers, the topic might be worth revisiting.
On whose authority?
The first thing to remember is that Canadian maintenance organizations are not an alternative to the licensed Aircraft Maintenance Engineer (AME). This becomes obvious when we look at the privileges of the most common kind of AMO, the Aircraft AMO. These organizations exist primarily to provide maintenance services to commercial air operators and flying training units. Notice the word perform. AMOs are not authorized to certify maintenance, although they are responsible for designating the qualified AMEs who will. If the work is performed off-aircraft (i.e. in the wheel and brake shop, or the battery shop), the AMO may authorize a non-licensed technician to sign the release, provided he or she meets the applicable qualifying standards specified in the AMO's approved manual. This privilege is usually referred to as an SCA (Shop Certifying Authority). Work performed on the aircraft itself may only be released by a licensed AME and that includes the installation of parts that have been previously released under an SCA.
The authorization of an AME to sign a release for on-aircraft work is known as an ACA (Aircraft Certifying Authority) and it may also include off-aircraft privileges. Regardless of whether a release is signed under an SCA or an ACA, the individual signing the release takes personal responsibility for the work certified. The signature is not made on behalf of the organization.
Aircraft AMOs are limited to the performance of non-specialized work; that is, work other than the specialized tasks listed in Schedule II of CAR 571. This is similar, but not identical, to the list of major repairs in FAR 43, Appendix A - the main difference being that the specialized work designation only takes into account the skill required to perform the work, and has no bearing on design approval issues. The AMO's ratings indicate the aircraft types it can maintain. The limitations listed against each rating indicate the scope of work that may be undertaken. The maximum permissible scope for an Aircraft AMO is "all non-specialized work."
So, given that the only privilege of an Aircraft AMO is to perform non-specialized work on commercially operated aircraft, and to authorize unlicensed personnel to sign a parts tag, what added advantage does the AMO confer, that makes it an essential element of the commercial aviation environment? The answer is "organization." An AMO has the benefit of an organized operating structure, ensuring that each individual works as part of a team. The organization, with obvious benefits for record keeping, communications, shift hand-over, establishes what procedures and standards to follow in a given case, not the AMEs. An Aircraft AMO can be regarded as a group of technicians and AMEs working in accordance with a previously established set of approved standards.
The specialized AMO
Specialized AMOs are quite different. Like Aircraft AMOs, they can do maintenance work in support of commercial aircraft, but their raison d''tre is to do work that is beyond the privileges of an Aircraft AMO. Specialized AMOs themselves can be divided into two sub-groups: Those with product ratings and those with process ratings
Aircraft and Shop Certification Authority in a Commercial Environment By Tony Soulis February 1998 Tony Soulis is Transport Canada's chief aircraft maintenance engineer, licensing...
Is It Manufacturing Or Is It Maintenance? It’s all in the certification By Brian Whitehead February 2001 Manufacturing and maintenance have a lot in common. Many of the same...
Undocumented Parts By Brian Whitehead May-June 1998 Brian Whitehead is chief of policy development for the Aircraft Maintenance & Manufacturing branch in Ottawa, Canada...
The Conditional Maintenance Release By Brian Whitehead March 1998 Brian Whitehead is chief of policy development for the Aircraft Maintenance & Manufacturing branch in Ottawa...