Action
Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
Summary
We are revising an earlier proposed airworthiness directive (AD) for certain The Boeing Company Model 767 airplanes. That NPRM proposed to require drilling a drain hole in the flanged tubes for certain elevator control cable aft pressure seals; doing repetitive inspections for dirt, loose particles, or blockage of the flanged tube and drain hole for the pressure seals, and corrective action if necessary; replacing the aft air-intake duct assembly with a new or modified assembly and installing a dripshield; and installing gutters on the horizontal stabilizer center section and modifying the side brace fittings. That NPRM was prompted by reports of stiff operation of the elevator pitch control system and jammed elevator controls. This action revises that NPRM by proposing to require replacement of pressure seal assemblies, rather than the proposed drilling of drain holes; revising a certain compliance time and inspection type; adding certain optional actions; and revising the applicability. We are proposing this supplemental NPRM to prevent moisture from collecting and freezing on the elevator control system components, which could limit the ability of the flightcrew to make elevator control inputs and result in reduced controllability of the airplane. Since these actions impose an additional burden over that proposed in the previous NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.