Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain Cessna Aircraft Company Model 500, 501, 550, 551, S550, 560, 560XL, and 650 airplanes. This proposed AD was prompted by multiple reports of smoke and/or fire in the tailcone caused by sparking due to excessive wear of the brushes in the air conditioning (A/C) motor. This proposed AD would require an inspection to determine the accumulated hours on certain A/C drive motor assemblies; repetitive replacement of the brushes in the drive motor assembly, or as an option to the brush replacement, deactivation of the air conditioner; and return of replaced brushes to Cessna. We are proposing this AD to prevent the brushes in the A/C motor from wearing down beyond their limits, which could result in the rivet in the brush contacting the commutator causing sparks and consequent fire and/or smoke in the tailcone with no means to detect or extinguish the fire and/or smoke.