CF-98-43 BELL

Applies to all Bell Helicopter Textron Canada (BHTC) Model 206 series helicopters equipped with crosstube assemblies (crosstubes) of older design having rivet holes in the support area designated for rivet-on supports with the following, but not limited to, part numbers:

(i) Aeronautical Accessories Inc.                          206-321-001 and -002

(ii) Airborne Supply Inc.                                       AB206-050-107-025 and -027
                                                                                 AB206-050-119-005 and -007

(iii) Bell Helicopter                                              206-050-107-011, -013, -025 and -027
                                                                               206-050-119-001, -003, -005 and -007
                                                                               206-050-134-001, -003, -005, -007, -009 and -011
                                                                               206-050-157-001 and -003
                                                                               206-050-169-001, -003, -011 and -013
                                                                               206-053-109-001, -003, -005 and -007
                                                                               206-053-119-001 and -003
                                                                               206-053-129-009, -011, -101 and -103

(iv) Other manufacturers, as approved by     Any of the above
the Federal Aviation Administration (FAA)
under Parts Manufacturer Approval (PMA)

Note: The riveted crosstubes of newer configurations, P/N 206-050-2xx-xxx and 206-053-2xx-xxx, having rivet holes only on the sides of the crosstube, are not affected by this directive.

Compliance is required as indicated, unless already accomplished.

The older versions of riveted crosstubes were subject to fatigue cracking; the large majority of cracks started at the top rivet holes under the support assemblies. A few started elsewhere at corrosion or mechanically damaged initiation points. Two accidents have been attributed to crosstubes breaking from cracks starting at the rivet holes. Since the issue of Airworthiness Directive CF-95-17, which introduced inspections, a total failure of an aft crosstube occurred just 40 hours air time after it was properly inspected. The crack had gone undetected under the strap assembly until progressing rapidly once near the strap's edge. Therefore, these older riveted configurations need to be retired within a reasonable time in service.

To prevent a possible catastrophic failure of the crosstube assemblies accomplish the following:

1.  Within the next 100 hours air time after the effective date of this directive, remove from the helicopter any crosstube of unknown history or having a total of six or more years in service.

2. No later than 31 December 2000, remove any of the affected crosstubes, regardless of time in service.

This directive becomes effective 15 February 1999.