Action
Supplemental notice of proposed rulemaking (SNPRM); reopening of comment period.
Summary
We are revising an earlier proposed airworthiness directive (AD) to supersede an existing AD for certain The Boeing Company Model 767 airplanes. The existing AD currently requires repetitive inspections to detect discrepancies of the wiring and surrounding Teflon sleeves of the fuel tank boost pumps and override/jettison pumps; replacement of the sleeves with new sleeves, for certain airplanes; and repair or replacement of the wiring and sleeves with new parts, as necessary. The first SNPRM proposed to reduce the initial compliance time and repetitive inspection interval in the existing AD. The first SNPRM also proposed to mandate a terminating action for the repetitive inspections, to eliminate wire damage. In addition, the first SNPRM proposed to remove certain airplanes from the applicability of the existing AD. The first SNPRM was prompted by fleet information indicating that the repetitive inspection interval in the existing AD is too long, because excessive chafing of the sleeving continues to occur much earlier than expected between scheduled inspections. This action revises the first SNPRM by also proposing to require revising the maintenance program to incorporate changes to the airworthiness limitations section. We are proposing this second SNPRM to detect and correct chafing of the fuel pump wire insulation and consequent exposure of the electrical conductor, which could result in electrical arcing between the wires and conduit and consequent fire or explosion of the fuel tank. Since these actions impose an additional burden over that proposed in the first SNPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.