The Federal Aviation Administration has filed a new airworthiness directive (AD) for several types of Airbus A300 aircraft due to reports of chafing between the autopilot electrical wiring and wing bottom skin.
The chafing could cause an uncontrolled fire if sparking is set off by flammable vapors near the wiring, says the FAA.
The airworthiness directive will require the operator to modify the wiring installation in zone 675 of the right-hand wing of the aircraft to better protect the wiring harness and improve its routing, according to the final rule.
A notice of proposed rulemaking in March had included a compliance time of 30 months or 4,500 flight hours after the AD is effective. UPS has indicated to the agency that it preferred to extend that timeline by an additional 10 months so that it could include the modification in C-checks, which the airline performs every 30 months. The operators said it also needed to plan for acquiring the parts, creating engineering orders and receiving the necessary approvals.
The agency responded that it would not change the compliance time in the AD, but that it would consider proposals from operators to extend the time if it is safe to do so.
The types affected include Airbus A300 B4-603, B4-605R and B4-622R variants, as well as the A300 C4-605R variant F aircraft and A300 F4-600R series.
The agency estimates that the AD will affect 132 US-registered aircraft a cost of $2,315, for a total cost of $305,580 for all aircraft affected by the AD. The agency foresees parts costing about $1,720 per aircraft and the modification taking about 7h to complete at a labour rate of $85 per hour.