Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to supersede airworthiness directive (AD) 2006-15- 08, which applies to all Honeywell International Inc. TPE331-1, -2, - 2UA, -3U, -3UW, -5, -5A, -5AB, -5B, -6, -6A, -10, -10AV, -10GP, -10GT, -10P, -10R, -10T, -10U, -10UA, -10UF, -10UG, -10UGR, -10UR, -11U, - 12JR, -12UA, -12UAR, and -12UHR turboprop engines with certain part numbers (P/Ns) of Woodward fuel control unit (FCU) assemblies, installed. AD 2006-15-08 currently requires initial and repetitive dimensional inspections of the fuel control drive spline for wear, and replacement of the FCU and fuel pump. Since we issued AD 2006-15-08, we determined that additional FCU assembly P/Ns are affected, the compliance deadline and assembly replacement after removal for cause or overhaul are no longer required, and that cautionary engine operating information must be observed. This proposed AD was prompted by reports of loss of the fuel control drive, leading to engine overspeed, overtorque, overtemperature, uncontained rotor failure, and asymmetric thrust in multi-engine airplanes. This proposed AD would require initial and repetitive dimensional inspections of the affected fuel control drive splines, and insertion of certain airplane operating procedures into the applicable flight manuals. We are proposing this AD to prevent failure of the fuel control drive that could result in damage to the engine and airplane.