Follows Several Reports Of Failure Of The Part Leading To In-Flight Shutdowns

The FAA has issued an Airworthiness Directive (AD) for the connecting rods in certain models of Lycoming engines, and asked for comments on the AD (2017-16-11).

The AD requires an inspection of connecting rods and replacement of affected connecting rod small end bushings. It was prompted by several reports of connecting rod failures resulting in uncontained engine failure and in-flight shutdowns (IFSDs).

The FAA says it has received 5 reports of uncontained engine failures and IFSDs due to failed connecting rods on various models of Lycoming Engines reciprocating engines listed in Table 1 of Lycoming Engines Mandatory Service Bulletin (MSB) No. 632B, dated August 4, 2017, that were overhauled or repaired using any replacement part listed in Table 2 of Lycoming Engines MSB No. 632B, dated August 4, 2017, which was shipped from Lycoming Engines during the dates listed in Table 2 of Lycoming Engines MSB No. 632B, dated August 4, 2017.

This AD requires accomplishing the instructions in Lycoming Engines MSB No. 632B, dated August 4, 2017, except for the instruction to complete the online survey as specified in the MSB. This condition, if not corrected, could result in uncontained engine failure, total engine power loss, IFSD, and possible loss of the airplane. The purpose of the AD is to prevent connecting rod failure, the agency says.

The FAA says this is an unsafe condition that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because compliance is required within 10 operating hours. Therefore, we find that notice and opportunity for prior public comment are impracticable and that good cause exists for making this amendment effective in less than 30 days. Comments are invited, however, and must be submitted by September 25, 2017.

The FAA estimates that the AD affects 778 engines installed on airplanes of U.S. registry. The cost of compliance with the inspection aspect of the AD AD, including labor, is estimated to be $1,425 per engine totalling $1,108,650.00 per inspection cycle for all U.S. operators.

If the connecting rods need to be replaced, the FAA estimates that the cost, including labor and parts, would be $2,170 per engine for four cylinders, $6,680 for six cylinders, and $6,850 for eight cylinders.

(Image from file)

FMI: AD