FAA Feedback: Q & A: FAR Compliance

Oct. 7, 2014
Single engine turbine aircraft must be inspected in accordance with FAR 91.409 inspections. This means that a single engine turbine powered aircraft must have either an annual or a progressive inspection performed every 12 calendar months.

The following are my answers to three questions submitted by Aircraft Technician magazine on behalf of individual technicians. In each case, the fax was “sanitized” so I never knew who or where the original letters came from. If any of the individuals involved have further questions on these subjects please call me at (202) 366-6382.

Question: Piper PA31T Cheyenne Manufacturer’s Inspection program recommends that you use hour increments only to measure the intervals between inspections. This is quite different from the hours and calendar time inspection requirements for a like model Beech aircraft. Is it possible for a PA31T Cheyenne that’s operated less than 50 hours a year to go two years before an inspection is performed?

Answer: Yes, it is possible to go almost two years between inspections. I too am a little uneasy about an inspection program without some calendar requirement to protect against long time intervals between inspections. It’s been my experience that an aircraft that sits for months at a time in the corner of a hangar is usually in worse shape for the experience that an aircraft that’s flown every day. However, in defense of the rule, the owner/operator still has the responsibility under FAR 91.403 to maintain that aircraft in an airworthy condition.

Question: What kind of inspection is required for single-engine turbine powered aircraft operated under Part 91?

Answer: Single engine turbine aircraft must be inspected in accordance with FAR 91.409 inspections. This means that a single engine turbine powered aircraft must have either an annual or a progressive inspection performed every 12 calendar months. If the aircraft is used for flight training or for hire, a 100-hour inspection must have been completed within the preceding 100 hours. All inspections must be consistent with the manufacturer’s recommendations and signed off in the maintenance record in accordance with FAR 43.11.

Under the new rule change in Part 91.409(c)(4), owners and operators of single- or multi-engine turbine helicopters – in lieu of annual, progressive or 100-hour inspections – now have the option to have their inspections performed in accordance with FAR 91.409(e). Under this rule change they can have their choice of four other additional inspection programs.

Question: A gentleman wrote in and wanted the procedure to get a 1931 Nicholas Beazley aircraft certificated in normal category. There was an additional problem. Instead of the original 80-hp Genet Mark II radial engine, he wanted to use a Lambert 90-hp radial engine.

Answer: I never heard of a Nicholas Beazley aircraft before, but I found it right in volume six, “Aircraft Listing,” of the type certificate data/specifications. Since the Genet radial was the only engine approved for this model aircraft there are only two options to get the aircraft flying again.

The first is to get a supplemental type certificate (STC). In order to get the aircraft approved in “normal” category with this engine installation, this is the only option. Since this kind of engine swap is so rare I recommend you contact the FAA Engine and Propeller Directorate, Aircraft Certification Service, 12 New England Executive Park, Burlington, MA 01803.

But first give Mark Fulmer, the manager of ANE-140, engine certification office a call at (617) 273-7080 and give him additional details on the engine change. Also ask him about the procedures for a one-time STC for the installation. A one-time STC takes less time to approve than a formal STC.

Once the STC is issued and you comply with its requirements ask the local Flight Standards District Office (FSDO) to issue you a standard airworthiness certificate for normal category operation. However, acquiring even a one-time STC will take time and, yes, money.

The second option is to get the aircraft certified in experimental/exhibition category. This can be accomplished by your local FSDO office. An airworthiness inspector, with a minimum amount of fuss and paperwork, will issue you an experimental/exhibition category special airworthiness certificate that will get you flying almost immediately. The downside of this procedure is that your aircraft is placed under more strict operating requirements than normal category operations.

This article first appeared in the May/June 1991 issue of Aircraft Technician