(4) Section 33.93(a), Teardown inspection, was revised to the current requirements.
(5) Section 33.99, General conduct of block tests, was revised to the current regulation by adding requirements for engine service, malfunction, and stoppage during endurance test.
c. Part 33, amendment 10, effective March 26, 1984.
(1) Section 33.87, Endurance test, was revised as follows:
(a) Sections 33.87(a)(3) and (a)(5) were revised to allow the applicant to reduce power or thrust or rotor speeds below the 100 percent value specified in § 33.87(a)(3) during maximum compressor air bleed runs, as it is not always possible to reach redline speeds at takeoff and maximum continuous thrust/power without exceeding gas temperature limits.
(b) Section 33.87(a)(6) was revised to allow separate rig testing of accessory drives and mounting attachments.
(c) A new requirement was added to specify that the rated 2½-minute OEI power must be applied during the last 25th cycle of the endurance test. Specifically, the 2½- minute OEI power must be applied during the last 5 minutes of the 30-minute run for the rated 30-minute OEI.
(d) The above changes updated §§ 33.87(a)(3), (a)(5), and (a)(6) to the current requirements.
d. Part 33, amendment 12, effective October 3, 1988.
(1) In § 1.1, the existing definitions of “2½-minute power” and “30-minute power” were revised to read: “2½-minute OEI power” and “30-minute OEI power” to make these definitions relate more closely to the name of these power ratings with their intended use. A new definition of “continuous OEI power” was introduced.
(2) In § 33.87, the new test schedule for an engine with a “continuous OEI power” rating was added to the endurance test as § 33.87(d).
e. Part 33, amendment 18, effective August 19, 1996.
(1) This amendment adopted new 30-second OEI and 2-minute OEI ratings applicable to rotorcraft turbine engines.
(2) New definitions of, “30-second OEI power” and “2-minute OEI power” ratings were introduced in § 1.1.
(3) Section 33.85 was revised by adding new paragraphs (c) and (d) to cover specific calibration test requirements for these two OEI ratings.
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(4) Section 33.87 was revised by adding a new 2-hour test schedule to paragraph (f) for the ratings.
(5) Section 33.93 was revised by adding new paragraphs (b) and (c) that define teardown inspection requirements after completion of the 2-hour endurance test in § 33.87(f).
f. Part 33, amendment 25, effective October 17, 2008. This change amended the endurance test and tear down inspection requirements for certain OEI ratings. This amendment was the result of a harmonization effort of a working group comprised of representatives of the FAA, the Joint Aviation Authorities (JAA), Transport Canada, and industry. The European Aviation Safety Agency (EASA) subsequently adopted these new requirements as part of its Certification Specifications for Engines.
(1) Revised § 1.1, General definitions, for all rated OEI powers by adding a second condition, an engine shutdown, to the failure condition that defines an OEI. Also revised the use for the 2½-minute OEI rating from “a period of use” to “periods of use” to be consistent with the usage definitions of 30-second OEI and 2-minute OEI ratings.
(2) Revised § 33.87(a)(6) to allow the applicant to run the tests under §§ 33.87(f)(1) through (f)(8) without loading the accessory drives and mounting attachments if the applicant can substantiate that the durability of any accessory drive or engine component is not significantly affected and if the equivalent power is added to the output drive shaft.
(3) Revised § 33.87(a)(5) to exempt engines with 30-second and 2-minute OEI ratings from testing with maximum air bleed if the applicant can show by testing, or analysis based on testing, that the validity of the endurance test is preserved.
(4) Added a requirement that the test schedule for 30-second and 2-minute OEI ratings in § 33.87(f) be run continuously without stopping.
(5) Clarified the test schedule in § 33.87(f)(4) related to 30-second and 2-minute OEI ratings.
(6) Revised the test schedule in § 33.87(c) related to 30-minute OEI rating to agree with the schedule in EASA’s certification specifications for engines. The result harmonizes the endurance test schedule for engines with a 30-minute OEI rating.
(7) Clarified the idle condition of § 33.87(f)(8) as flight idle.
(8) Revised § 33.93(b)(2) by replacing the parts or components identified as, “mounts, cases, bearing supports, shafts, and rotors,” with, “the engine,” to emphasize that after the test, the applicant needs to inspect and consider deterioration of any engine component that could affect the structural integrity of the engine, not just those listed above.
g. Part 33, amendment 30, effective November 2, 2009. This amendment added the transient engine overtorque and maximum engine overtorque. This amendment harmonized A12-5
FAA and EASA standards and simplified airworthiness approvals for the import and export of turbopropeller and turboshaft engines with free power turbines.
(1) Added in § 1.1, General definitions, the maximum engine overtorque.
(2) Added new engine limitations in § 33.7(16) for transient engine overtorque and § 33.7(17) maximum engine overtorque for turbopropeller and turboshaft engines incorporating free power turbines.
(3) Added new section, § 33.84, engine overtorque test that contains requirements for testing performed under § 33.87 endurance test.
(4) Revised § 33.87(a)(8) by adding the transient engine overtorque.
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_________________________________________________________________ _________________________________________________________________ _________________________________________________________________ ________________________________________________________________ Appendix 13. Advisory Circular Feedback Information If you have comments or recommendations for improving this AC, or suggestions for new items or subjects to be added, or if you find an error, you may let us know about it by using this page as a template and 1) emailing it to 9-AWA-AVS-AIR500-Coord@faa.gov, or 2) faxing it to the attention of the AIR Directives Management Officer at 202-267-3983.
Subject: (insert AC number and title) Date: (insert date)
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(briefly describe what you want added attaching separate sheets if necessary) Name: __________________________ A13-1