Corrosion Found on Learjet 40 and 45 TFE731-20s
Bombardier has notified Learjet 40 and 45 operators that the aft, front frame flange of the TFE731-20 engine, and the thrust reverser flanges, may be susceptible to corrosion. The company recently discovered the problem. “Of the approximately 520 Learjet 40/40XR/45/45XRs in service, about 350 may be affected because the manufacturer introduced composite bypass ducts without adequate protection of the adjacent aluminum structure. To date there have been only a few known occurrences of corrosion,” a Bombardier spokeswoman told AIN. Bombardier is working in conjunction with Honeywell and Nordam to develop a program to conduct inspections and any necessary repairs. Learjet, Honeywell and Nordam are expected to release service bulletins before year-end. “Learjet strongly recommends that customers wait until they are scheduled by the fielding team to perform any inspections related to this issue. This will ensure adequate logistical support is in place. Based on a preliminary engineering assessment and feedback obtained from Honeywell's analysis, owners and operators can continue to operate their aircraft as normal until their scheduled inspection. No action is required at this time,” the spokeswoman said.