A-90-165
NTSB Safety Recommendation — Aviation
Recommendation text
THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: REQUIRE TEXTRON LYCOMING TO ISSUE A SERVICE BULLENTIN INCORPORATING A NEW, IMPROVED DESIGN MODIFICATION TO THE MODEL TIO-540-S1AD ENGINE EXHAUST SYSTEM IN ORDER TO PREVENT IN-FLIGHT ENGINE FIRES RESULTING FROM FAILURE/SEPARATION OF THE LEFT INTERMEDIATE EXHAUST PIPE. THE MODIFICATION SHOULD BE BASED ON CONSIDERATION OF THOSE ASPECTS WHICH MAY EFFECT THE ASSEMBLY, INSTALLATION, AND INTEGRITY OF THE LEFT INTERMEDIATE EXHAUST PIPE, E.G., EXHAUST PIPE FLANGE THICKNESS/FLATNESS, V-BAND COUPLING DESIGN, EXHAUST PIPE ALIGNMENT TOLERANCES, VIRBRATION, FATIGUE CHARACTERISTICS, ADEQUACY OF SLIP JOINTS, AND THE NEED FOR ANY SUPPLEMENTAL STRUCTURAL OF THE EXHAUST PIPE. (URGENT)
In plain language (FlightFinder summary)
The NTSB asks the FAA to require Textron Lycoming to issue a service bulletin incorporating a new design modification for the TIO-540-S1AD engine exhaust system. This modification should address factors like flange thickness, V-band coupling design, alignment tolerances, vibration, fatigue, slip joints, and additional structural support to prevent in-flight engine fires caused by failure or separation of the left intermediate exhaust pipe. The recommendation is marked urgent.
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 Action |
|---|---|
| Mode | Aviation |
| Closed | May 6, 1993 |
| NTSB number | SEA90FA129 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).