Transport i infrastruktura · 16/11/1994

Airworthiness Directives; Boeing Model 727 Series Airplanes

This amendment supersedes an existing AD that currently requires periodic leak checks of the forward lavatory drain system and provides for the installation of a new drain valve as terminating action. This action continues to require various leak checks, but deletes a previously provided terminating action; adds requirements for leak checks of other lavatory drain systems; provides for the option of revising the FAA-approved maintenance program to include a schedule of leak checks; requires the installation of a cap on the flush/fill line; and requires either a periodic leak check of the flush/fill line cap or replacement of the seals on both that cap and the toilet tank anti- siphon (check) valve. This amendment was prompted by continuing reports of damage to engines and airframes, separation of engines from airplanes, and damage to property on the ground, caused by ``blue ice'' that had formed from leaking forward lavatory drain systems and subsequently had dislodged from the airplane. The actions specified by this AD are intended to prevent such damage associated with the problems of ``blue ice.''