Bell 407 tail boom separation requires FAASTeam caution

The Bell 407 tail boom separation in June prompted the FAA’s FAASTeam to issue a special message reminding all operators of the current FAA Airworthiness Directive (AD) 2012-18-09 to check boom attachment torque every 300 hours. . The NTSB’s investigation into a plane crash in Hawaii that seriously injured three of the six people on board is ongoing.

On June 8, the helicopter, registration N402SH, operated by K&S Helicopters, trading as Paradise Helicopters, crashed into a lava field near Calea. The tail ball was found approximately 762 feet northeast of the main crash site.

The tail spar 407 is attached to the intermediate fuselage with bolts, washers and nuts that connect the four aft spars of the fuselage to the four matching spars located at the forward end of the spar. After the accident, the operator decided to replace the tail boom mount on the remaining five Bell 407s. Before removing the hardware, the operator inspected the mount and found no evidence of loose hardware, but eddy current nondestructive inspection of the aft fuselage spars revealed cracks on two of those five 407s.

Since 2007, there have been several bulletins and announcements related to the Bell 407 tail spars regarding aft fuselage and bulkhead skins, mounting replacement and torque checks, installation of outer strap doublers on the upper left spar, and instructions for repairing cracked spars.