AD NUMBER: 2018-16-51

PRODUCT: Bell Helicopter Textron Canada Limited (Bell) Model 429 helicopters.

ACTION: Final rule; request for comments.

SUMMARY: This AD was sent previously to all known U.S. owners and operators of these helicopters as Emergency AD 2018-16-51, dated July 26, 2018, which superseded Emergency AD 2018-15-51, dated July 20, 2018.

This AD requires inspecting the tail rotor (T/R) gearbox installation, inspecting the T/R gearbox retaining hardware and support attachment point areas, and replacing each nut.

This AD is prompted by two reports of T/R gearbox assemblies loosely attached to the gearbox support.

DATES: This AD becomes effective November 6, 2018 to all persons except those persons to whom it was made immediately effective by Emergency AD 2018-16-51, issued on July 26, 2018, which contains the requirements of this AD. Comments must be received by December 21, 2018.

COST: The FAA estimates that this AD affects 90 helicopters of U.S. Registry. The cost of compliance is estimated as follows:

Labor costs are estimated at $85.00 per work-hour.

• Inspecting the T/R gearbox installation takes about 0.25 work-hour for an estimated cost of $21 per helicopter and $1,890 for the U.S. fleet.
• Inspecting the T/R gearbox retaining hardware and the support attachment points takes about 0.5 work-hour for an estimated cost of $43 per helicopter and $3,870 for the U.S. fleet.
• Replacing the nuts takes about 1 work-hour and parts cost about $20 for an estimated cost of $105 per helicopter and $9,450 for the U.S. fleet.

FMI: AD