Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Learjet Model 60 airplanes, that currently requires inspection to detect bends in or damage to the fuel crossflow tube; inspection to determine clearance between the fuel crossflow tube and the flight control cables; and replacement or repair of the tube, if necessary. This action would require a review of airplane maintenance records or an inspection to determine if a fuel crossflow tube having a certain part number is installed; and follow-on/corrective actions, as applicable. This action also would expand the applicability of the existing AD to include additional airplanes. The actions specified by the proposed AD are intended to prevent chafing and consequent failure of the fuel crossflow tube due to inadequate clearance between the tube and the flight control cables, which could result in loss of fuel from one fuel tank during normal operating conditions or loss of fuel from both main fuel tanks during fuel cross-feeding operations. This action is intended to address the identified unsafe condition.