Bell 206 series - Service Difficulty Advisory

AV 1999-03R1
14 January 2000

Cracked frame

This revision to AV-99-03, dated 15 July 1999, has been published to clarify the description of the affected hardware and to correct the references to the Illustrated Parts Breakdowns.

An SDR reported cracks under the nutplates on the passenger seat bulkhead frame P/N 206-033-107-049 on a Model 206L helicopter. The correct attach screws P/N 120-079-10-12 and washers P/N 140-017-10SC had been replaced with unauthorized AN970 washers and AN3 bolts, which are longer than the original screws. The installation of the AN3 bolts indented the frame, initiating the fatigue cracking.

If left uncorrected, the integrity of the frame is compromised and the damage may spread to surrounding structures. Cracks were also reported on the inner skin and these could migrate up to the frame.

This cracking can only be found after removal of the interior. Therefore, Transport Canada strongly recommends an immediate inspection to confirm the use of the proper screws and washers at this location as per the applicable Illustrated Parts Breakdowns (IPB). If a substitute bolt is found, the removal of the interior and close inspection of the frame for cracking is required.



The following Bell Illustrated Parts Breakdowns refer:



  • BHT-206A/B Series IPB - Fig. 25-9,53-16, items 25 and 26; 28, 39, 40; Fig. 25-1253-17,, items 5 and 6. 38; and Fig. 53-20, items 39 and 40.
  • BHT-206L -Series IPB - Fig. 25-4, 53-25, items 68 and 6921, 22, 27, 28; Fig,. 25-653-28, items 108 and 109. 19, 44; Fig. 53-26, items 33, 34.

For further information contact a Transport Canada  Centre, or call Mr.  Bogdan  Gajewski, Continuing Airworthiness, Ottawa, telephone (613)  952--4450, facsimile (613) 996-9178 or   e-mail

For Director, National Aircraft Certification

B. Goyaniuk
Chief, Continuing Airworthiness