rotormatic Posted February 2, 2003 Report Share Posted February 2, 2003 INFORMATION LETTER 407-03-68TO: All Owners/Operators of Bell 407 series HelicoptersSUBJECT: BELL 407 MAST – INCIDENT REPORT This Information Letter is issued to advise of an unusual incident and to stressthe importance of adhering to the published Bell 407 maintenance procedures. On 9 January 2003, a Bell 407 was flying in the Gulf of Mexico when the pilotheard a noise, detected a vibration, and returned to his base for an investigation.Visual inspection found a crack indication in the mast pole below the swashplatedrive hub and above the swashplate boot. The crack extended circumferentially around approximately 40% of the mast outer diameter. This is the first reported occurrence of this nature since Bell 407 deliveries began in January 1996. While the cause of the crack has not yet been determined, preliminaryinvestigation reveals that the mast pole had been painted in the cracked areaand that corrosion was also visible. In view of the above the following points arestressed: · As noted in the CR&O manual the mast pole is not to be painted in thatarea; · Routine inspection is necessary to detect and remedy any sign ofcorrosion during daily checks and scheduled inspections. The Bell 407 comprises approximately 545 aircraft and has accumulated close to800,000 flight hours. Bell Helicopter has given this investigation the highestpriority and operators will be informed of the results and further action if any, assoon as possible. Quote Link to comment Share on other sites More sharing options...
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