54-20-01 AIRCRAFT BELT AND TRIM (SAFETY BELT): Applies to Model LBM-1900 (Dwg. No. 19001) Safety Belts Manufactured Prior to April 1, 1954.
Compliance required as soon as possible but not later than March 1, 1955.
Based on a complaint alleging noncompliance with strength standards of FAA Technical Standard Order C22, verification tests were conducted by the National Bureau of Standards at FAA request, which revealed that the belt assemblies of this make and model manufactured prior to April 1, 1954, with LBM-1900-3 and -3A buckles, were under strength for a majority of specimens tested. These tests are considered as evidence of nonconformance with terms of the TSO.
Therefore, TSO-labeled belts of this model as noted above which were manufactured prior to April 1, 1954, can no longer be considered as complying with the prescribed airworthiness standards and, accordingly, must not be used in civil aircraft.
Belts of this model manufactured subsequent to April 1,1954, incorporate a buckle of improved design and tests reveal this belt assembly to be in accordance with TSO-C22 tension test requirements.
This supersedes AD 54-03-01.