Opportunity; Maintenance, repair and alteration under the ASTM consensus standard

Maintenance, repair and alteration under the ASTM consensus standards


Paperwork is different with LSA, and it is not unusual for an S-LSA to show up for maintenance with incorrect records, according to Paradis and other AMTs I’ve talked to. These problems often stem from an uninformed A&P failing to appreciate the system of manufacturer-controlled maintenance, and thinking he or she is operating in the Standard class system of FAA-controlled maintenance. Worse, the actual work done on the S-LSA that lies behind those erroneous maintenance records is often at odds with the manufacturer’s maintenance manual, which is the maintenance bible for these aircraft, not AC 43.13. This fundamental misunderstanding is often reflected in an AMT sending the FAA a Form 337, which has no place in the ASTM-defined maintenance system.

Not only does the S-LSA manufacturer’s maintenance manual define how maintenance is to be preformed, but it also prescribes what tasks can be undertaken, and by who. F2295, the standard for continued operational safety monitoring of LSAs, varies substantially from the Airworthiness Directives system familiar to most AMTs, and needs to be understood as well.

S-LSA maintenance basics

Any maintenance, repair, inspection, or alteration for which instructions are provided in the maintenance manual is defined as “minor.” Any such activities not detailed in the manual are “major.” “Heavy” maintenance requires specialized training, equipment, or facilities, as determined by the manufacturer. “Line” maintenance includes tasks not defined as heavy that are approved by the manufacturer and specified in the manual. “Overhaul” includes activities that may only be accomplished by the manufacturer, or at a facility specifically approved by the manufacturer. While these definitions, abbreviated here, are a little confusing, they appear to have some overlap, and raise additional questions of interpretation, the point is that they are defined either by an applicable ASTM standard or the manufacturer, not by any FAR, Advisory Circular, or other FAA guidance. The manufacturer controls the maintenance process.

Any maintenance, repair, or alteration not specified in the maintenance manual must be accomplished pursuant to specific instructions from the manufacturer, which will issue a Letter of Authority (LOA) to the owner and AMT. This LOA must be made part of the aircraft’s permanent maintenance records. (Do not send it to the FAA!) Some manufacturers are better than others in managing this procedure in actual practice, and many S-LSAs are technically no longer in a condition for safe flight due to failure to comply with this process.

Manufacturers’ manuals also specify who may perform maintenance and required annual condition inspections on S-LSAs. Generally, this will be either an A&P mechanic (Inspection Authorization not required), a Light Sport repairman with a maintenance rating, LSR-M, or an employee of a certified repair station rated for this type of work. Holders of Sport and higher pilot certificates may also perform specified maintenance tasks. Again, it is all laid out in the manufacturer’s maintenance manual, which is itself issued pursuant to requirements of ASTM Standard F2483.

Controversial issues

Two trouble spots have lately developed between ASTM and type certificated aircraft worlds. First, as part of the basic concept of manufacturer-controlled maintenance, it was initially thought that airframe and engine manufacturers of ASTM-compliant products could require that AMTs take factory-approved training before they could work on their products, and many manufacturers have done so. Rotax, whose engines are in about 80 percent of S-LSAs manufactured today, is the best example of this.

Many of the manufacturers of Rotax-powerd S-LSAs, in turn, have made Rotax factory training a requirement of their aircraft maintenance manuals by requiring that the Rotax requirements be met. On Feb. 12, 2012, the Office of the Chief Counsel of the FAA issued a letter opining that manufacturers cannot legally require AMTs to obtain factory training before working on their products. This opinion surprised many in the industry since it seems to be at odds with the notion that the ASTM consensus standard system is controlled by the manufacturers. It is likely we have not seen the end of this controversy.

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