Jump to content

407 mast failure


Recommended Posts


TO: All Owners/Operators of Bell 407 series Helicopters



This Information Letter is issued to advise of an unusual incident and to stress

the 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 pilot

heard 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 swashplate

drive 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, preliminary

investigation reveals that the mast pole had been painted in the cracked area

and that corrosion was also visible. In view of the above the following points are



· As noted in the CR&O manual the mast pole is not to be painted in that



· Routine inspection is necessary to detect and remedy any sign of

corrosion during daily checks and scheduled inspections.


The Bell 407 comprises approximately 545 aircraft and has accumulated close to

800,000 flight hours. Bell Helicopter has given this investigation the highest

priority and operators will be informed of the results and further action if any, as

soon as possible.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...