What Makes Up the Inspection Program for Turbine Aircraft?
Part 3 of 3
By Joe Hertzler
This is the third of a three part series dedicated to understanding aircraft inspection programs, primarily twin-turbine powered aircraft inspection programs. In this article we will delve into 14 CFR Part 135 inspection program requirements.
Nine or less vs ten or more
Part 135 has two major maintenance categories — one for aircraft configured for seating capacity of 9 passengers or less and the other for seating capacity of 10 passengers or more. This distinction is found in 14 CFR Part 135.411.
14 CFR Part 135.411
"(a) This subpart prescribes rules in addition to those in other parts of this chapter for the maintenance, preventive maintenance, and alterations for each certificate holder as follows:
(1) Aircraft that are type certificated for a passenger seating configuration, excluding any pilot seat, of nine seats or less, shall be maintained under parts 91 and 43 of this chapter and §§ 135.415, 135.416, 135.417, and 135.421.
(2) Aircraft that are type certificated for a passenger seating configuration, excluding any pilot seat, of ten seats or more, shall be maintained under a maintenance program in §§ 135.415. 135.416. 135.417, and 135.423 through 135.443."
In general terms, the difference between these two categories is that aircraft with 10 or more passenger seats must be maintained under a maintenance program (Ref Parts 135.423 through 135.443). Such a maintenance program must be developed as part of the air carrier certification process or when adding a 10 or more aircraft to an existing certificate.
The nine or less aircraft operating under Part 135 must be maintained just like aircraft under Part 91 with the addition of the requirements defined in 135.421.
Its more than an inspection program — it’s a maintenance program
One significant difference to point out when comparing Part 91 maintenance requirements to Part 135 maintenance requirements is found by comparing the following abbreviated rules:
14 CFR Part 91.409 (e) "Large airplanes — and emergency equipment, is inspected in accordance with an Inspection program—in lieu of an inspection option of 91.409(f)."
14 CFR Part 135.421 (a) "Each Certificate holder who operates an aircraft type certificated for a passenger seating configuration, excluding any pilot seat, of nine seats or less, must comply with the manufacturer’s recommended maintenance programs, or a program approved by the Administrator, for each aircraft engine, propeller, rotor, and each item of emergency equipment required by this chapter."
14 CFR Part 135.425 "Each Certificate Holder shall have an inspection program and a program covering other maintenance, preventive maintenance, and alterations—"
In this comparison, we see Part 91.409 (e) states that an aircraft must be "Inspected," whereas Part 135 states that aircraft operated under that Part shall be maintained in accordance with a "Maintenance Program."