On Monday the FAA released new guidance that provides a method of compliance for the test requirements of 14 CFR § 33.84 – engine overtorque test – when the applicant chooses to run that test as part of the endurance test of § 33.87. The new guidance is AC 33.87-1A and can be found on the FAA’s website at http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_33_87-1A_.pdf.
The AC also provides information and guidance on the test requirements of § 33.85 (calibration test), § 33.87 (endurance test), and § 33.93 (teardown inspection).
The guidance is directed at engine manufacturers and engine type-design applicants, as well as foreign regulators and FAA designees. However, it is still worth reviewing the guidance to determine whether there are any ways in which you might be affected.
The AC explains that the primary effect of the guidance is to eliminate some previously approved methods of engine testing that were designed to represent expected in-service operations rather than the endurance cycle described in § 33.87. This is because § 33.87 is not intended to reflect in-service operation, but rather to demonstrate a minimum level of operability and durability throughout the engine’s assigned ratings and limitations.
We encourage all of our members to take a look at this (and any other) new guidance to make sure there are no surprises. If you see anything that concerns you please let MARPA know!