AOPA says the that service bulletins aren't mandatory for Part 91 aircraft owners, regardless of what the NTSB says. And now AOPA is asking the FAA to remain firm in upholding that longstanding policy and interpretation of the law.

"The FAA's past and present opinion is that while service bulletins and instructions are not mandatory, they may be used by mechanics as an acceptable method, but not the only method, to show compliance with the regulations when performing maintenance, alterations, or preventive maintenance," AOPA Executive Vice President of Government Affairs Andy Cebula said in a letter to Nicholas A. Sabatini, the FAA's associate administrator for aviation safety.

"Should the FAA deem it necessary to issue a letter of interpretation in the interest of clarity and to avoid misapplication of existing regulations, the agency must reaffirm that service bulletins and service instructions are not mandatory for general aviation.... A manufacturer is not allowed to unilaterally require compliance with future service bulletins or instructions," said Cebula.

The issue was raised by the NTSB's ruling in the case of Administrator v. Law, in which a mechanic was accused of performing unairworthy repairs. In essence, the FAA claimed the mechanic used procedures not approved by the administrator.

But the NTSB took it a step farther, saying that "by not using the manufacturer's prescribed inspection technique, [the] respondent violated the regulations...."

That language would seem to require compliance with service bulletins or service instructions, known and yet to be issued, when referenced by the manufacturer's maintenance manual.

For general aviation aircraft certificated under CAR 3 (the majority of GA aircraft, designed before 1972), that's not the law. Any mandatory changes, repairs, or upgrades to an aircraft must be FAA approved and must go through the rulemaking process, including public comment, as required by the Administrative Procedures Act.

(For newer aircraft certificated under Part 23, service bulletins can be made mandatory if approved by the FAA and incorporated into the airworthiness limitations section of the aircraft's maintenance manual or instructions for continued airworthiness. Also, service bulletins are usually mandatory for aircraft flying in commercial service.)

In the case of Administrator v. Law, the FAA filed an appeal brief clearly stating that the mechanic was not in violation of the regulations for failing to follow the manufacturer's service bulletins, but rather for failing to use acceptable practices. "Why NTSB failed to mirror the FAA's language in their decision is a mystery," Cebula said.

AOPA told the FAA that the association was "concerned that the language used by the NTSB in their decision is contrary to established policy, practice, and law, and that mechanics and possibly FAA inspectors could misinterpret the NTSB's decision to require compliance with all manufacturers' service bulletins and instructions."

As FAA rulings have made clear through the years, following acceptable procedures does not necessarily mean mandatory adherence to service bulletins unapproved by the FAA.

FMI: www.ntsb.gov