A-90-090
NTSB Safety Recommendation — Aviation
Recommendation text
THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: AMEND 14 CFR PART 33 TO REQUIRE THAT TURBINE ENGINES CERTIFICATED UNDER THIS RULE ARE EVALUATED TO IDENTIFY THOSE ENGINE COMPONENTS THAT, IF THEY SHOULD FRACTURE AND SEPARATE, COULD POSE A SIGNIFICANT THREAT TO THE STRUCTURE OR SYSTEMS OF AN AIRPLANE; AND REQUIRE THAT A DAMAGE TOLERANCE EVALUATION OF THESE COMPONENTS BE PERFORMED. BASED ON THIS EVALUATION, REQUIRE THAT THE MAINTENANCE PROGRAMS FOR THESE ENGINES INCLUDE INSPECTIONS OF THE CRITICAL COMPONENTS AT INTERVALS BASED UPON THE CRACK SIZE DETECTABLE BY THE INSPECTION METHOD USED, THE STRESS LEVEL AT VARIOUS LOCATIONS IN THE COMPONENT, AND THE CRACK PROPAGATION CHARACTERISTICS OF THE COMPONENT MATERIAL. (Supersedes Safety Recommendation A-89-097)
In plain language (FlightFinder summary)
The NTSB asks the FAA to amend 14 CFR Part 33 to require that turbine engines be evaluated for components whose fracture and separation could threaten airplane structure or systems, and that a damage tolerance evaluation of those components be performed. Based on the evaluation, the FAA should require that maintenance programs for these engines include inspections of critical components at intervals determined by detectable crack size, stress levels at various locations, and the material's crack propagation characteristics.
This plain-language summary is written by FlightFinder to explain the recommendation above. It is not the official wording — the verbatim NTSB text is quoted above.
Details
| Status | Closed - Acceptable Alternate Action |
|---|---|
| Mode | Aviation |
| Closed | May 28, 1993 |
| NTSB number | DCA89MA063 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).