Airworthiness in Operation

Some form of the word “airworthy” appears exactly 100 times in 14 CFR part 91.

Who knew?

It’s a good bet that most aviation-savvy people in the United States think of part 91 as the basic “rules of the road” for safe flying: Pass on the right (§ 91.113(f)); no hotdogging (§ 91.303); don’t be an idiot (§ 91.13); that sort of thing.

They’re right. Part 91 is the basic regulatory bible for flying throughout the aviation world, thanks to its adoption by many nations as aviation matured. A fundamental, indispensable component of aviation safety is airworthiness. Is it any wonder, then, that part 91 has so much to say about that single word?

The first thing part 91 says about airworthiness is that it’s the mechanic’s responsibility. No wait – that’s not right. It’s the repair station’s responsibility. No, it’s the FAA inspector’s responsibility. Of course not! Read the news, for gosh sake: it’s the manufacturer’s responsibility!

Um ... No, that isn’t right either. “The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight.” (§ 91.7(b)) And it doesn’t say which pilot; it’s not just the airline transport pilot or the commercial pilot; it’s every pilot in command. (Actually, the very first thing part 91 says about airworthiness is, “No person may operate an aircraft unless it is in an airworthy condition.” (91.7(a)) That seems so obvious. Then again, I once knew a guy….)

Another point part 91 makes about this fundamental requirement is, “the owner or operator of an aircraft is primarily responsible for maintaining that aircraft in an airworthy condition….” (§ 91.403(a)). So far, owners, operators and pilots in command all share responsibility for airworthiness. Add one more person to the list: when a fractional ownership program aircraft is maintained under a Continuous Airworthiness Maintenance Program (CAMP), the program manager “is primarily responsible for … maintaining the airworthiness of the program aircraft, including airframes, aircraft engines, propellers, rotors, appliances and parts.” (§ 91.1413(a)).

Although operators in general are tagged with primary responsibility for maintaining the airworthiness of their aircraft in § 91.403(a), U.S. regulations call out some for special mention. Commuter and on-demand commercial operators (§ 135.413(a)), operators of “commercial aircraft” with 20 or more passenger seats or a payload capacity of 6,000 pounds or more not in common carriage (§125.243(a)) and airlines (§ 121.363(a)) all have additional requirements for establishing and maintaining the airworthiness of aircraft, including ensuring required maintenance is performed. While an airline may make arrangements with another person for the performance of any maintenance, preventive maintenance or alterations, it does not relieve the airline of its responsibility (§ 121.363(b); § 135.413(b) is similar).

Interestingly, among all the professionals who touch aircraft, mechanics and repair stations do not have primary responsibility for airworthiness of the aircraft under the regulations. While maintenance providers have plenty of related responsibilities — see §§ 43.13 and 145.205, for example — the regulations do not place “primary responsibility” on the shoulders of mechanics and repair stations.

FAA regulations specify that owners and operators both have “primary responsibility” for maintaining airworthiness, and pilots in command have the duty to assure the aircraft is, in fact, airworthy before each flight. In common law, this would be called “joint and several liability,” meaning that, if several people are caught napping, they all share in the liability, sometimes equally, sometimes in proportion to their fault. But if only one person gets caught, that person bears the entire liability. The term “joint and several liability” is not used in aviation regulatory law, but the concept is the same.

For example, § 121.363, which makes the airline “primarily responsible” for airworthiness, does not relieve pilots in command of their individual responsibility under § 91.7. In a 2010 NTSB case, the FAA “ordered a suspension of respondents’ airline transport pilot (ATP) certificates for a period of 180 days each” for violation of section § 91.7(b) and other regulations following a maintenance acceptance flight during which wing spoilers were seen to be “floating,” which is not a good thing. The pilots had allegedly failed to heed before taking off, a warning on the airline aircraft’s Electronic Centralized Monitor (ECAM) that a spoiler servo-jack had failed. The FAA’s case collapsed when they failed to prove that the ECAM had correctly indicated the problem, not because the airline’s regulatory responsibility for airworthiness relieved the pilots of theirs, nor because a maintenance provider had failed to repair or install the servo-jack correctly.

So, as owners or operators or pilots in command, the burden is on us to know when our aircraft is airworthy. How can we tell? Does the aircraft have to be perfect? Does our knowledge of it have to be perfect?

We’ll look at that next time.