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Regulatory Brief -- Defective Teledyne-Continental Motors crankshafts may ground over 3,000 aircraft for more than five monthsRegulatory Brief -- Defective Teledyne-Continental Motors crankshafts may ground over 3,000 aircraft for more than five months

Regulatory Brief

Defective Teledyne-Continental Motors crankshafts may ground over 3,000 aircraft for more than five months

The issue:

In April of 1999, Teledyne-Continental Motors (TCM) issued Critical Service Bulletin CSB-99-3A that cited seven crankshaft fractures that have occurred on low time engines manufactured during 1998. To prevent any further crankshaft failures TCM�s Critical Service Bulletin mandates an ultrasonic inspection within the next ten hours time in service (TIS) for crankshafts with 300 hours or less, or within the next 50 hours TIS for crankshafts with over 300 hours. TCM has a small number of inspectors in place throughout the country to conduct the required ultrasonic inspections.

The importance to our members:

There are approximately 3,000 engines affected by this CSB. Sources at TCM indicate that the engine manufacturer contracted an engineering firm to conduct the highly specialized ultrasonic inspections. Due to the specialized nature of the inspection process, very few technicians are certified to complete the required ultrasonic inspection. Consequently, affected aircraft owners may be grounded as long as five months before a qualified TCM representative is available to conduct the required inspection.

Significant provisions:

  • The cited seven crankshaft fractures occurred on engines with less than 175 hours TIS. All of the fractures have been grouped around certain manufacturing periods, however, TCM has implemented a much wider inspection program that covers new and rebuilt crankshafts processed at any time during 1998.
  • Engines affected: O-470, IO-470, TSIO-470, IO-520, TSIO-520, LTSIO-520, GTSIO-520, IO-550, and TSIOL-550 new and rebuilt engines utilizing a new or rebuilt crankshaft that was manufactured or rebuilt between January 1998 and December 1998.
  • The required ultrasonic inspection will be conducted by TCM personnel and will take roughly � day to complete.
  • TCM will pay for the required ultrasonic inspection and any necessary maintenance action. Additionally, TCM has contracted an engineering firm to conduct the required ultrasonic inspections. At present, there are a relatively small number of qualified TCM representatives available to conduct the ultrasonic inspection. TCM is currently conducting training classes to increase the number of factory authorized inspectors in the field.

AOPA position:

AOPA maintains that a potential five-month (or even a three month) aircraft downtime would be unacceptable. Long periods of aircraft grounding, such as this one, can have a substantial financial impact upon affected aircraft owners. These owners must continue to pay aircraft loans, monthly hangar or tie-down rental fees, chart subscriptions, costly GPS database subscriptions, and aircraft insurance premiums regardless of whether or not their aircraft are flying. AOPA believes that the potential adverse economic impact of grounding over 3,000 aircraft for up to five months demands serious attention and consideration on the part of Teledyne-Continental Motors. It is AOPA�s sincere hope that TCM recognizes and fully understands the impact of any extended periods of aircraft grounding and makes every effort to substantially reduce the downtime for affected aircraft owners.


On April 28, 1999, AOPA president Phil Boyer sent a letter to the president of TCM, Bryan Lewis. The letter highlighted AOPA�s concerns and strongly urged TCM to make every effort to keep aircraft downtimes to an absolute minimum. On May 7, 1999, AOPA President Phil Boyer held a telephone conference with TCM President Bryan Lewis following up on AOPA�s April 28 th letter concerning CSB 99-3A and its associated AD. TCM reported the following:

  • TCM is training an additional 20 inspectors and will have 40 inspectors in the field conducting inspections no later than May 11.
  • Owners of affected aircraft must log onto the TCM website at or call TCM at 888-200-7565 to register and find the designated inspection station nearest to their location.
  • TCM has sent guidance to each of the FBOs conducting the inspections indicating that the aircraft should be properly prepped in advance of the arrival of the inspection team. If cylinders are not removed and the FBO has not prepared the aircraft for inspection, the TCM authorized inspectors will move onto the next scheduled location and another team will return at a later date to complete the inspections. Owners must ensure that the FBO properly prepares their aircraft prior to the arrival of the inspection team from TCM.
  • Provided the aircraft have been properly prepared, the required ultrasonic inspection should take only a few minutes to complete. If aircraft are properly prepped, the inspection teams can conduct 80-100 inspections per day.
  • Initially, 20 TCM qualified inspectors will be conducting inspections at a number of centrally located FBOs throughout the country. The additional 20 newly trained inspectors will begin conducting the remaining inspections at additional locations throughout the United States. A list of primary and alternative inspection cites is located at In addition inspectors will remain in the field to "mop up" the aircraft that were scheduled too late to meet the initial inspection process or were not prepped prior to the arrival of the initial TCM inspection team.
  • TCM is leasing aircraft and flying the inspection teams from one FBO to another to conduct the scheduled ultrasonic inspections. Again, the initial inspection teams are spending only one day at each location so owners must ensure that their engines are opened up and ready to be inspected prior to the arrival of the TCM inspection team. If the aircraft is not properly prepped, the owner will have to wait an indeterminate amount of time for the secondary inspection teams to arrive.

On September 15, 1999, the FAA issued AD 99-19-01, which superceded the previously issued priority letter AD 99-09-17. In the new AD, the FAA expanded the applicability of the required inspections to GTSIO-520 engines and some additional engines identified by serial number. Additionally, the FAA increased the time in service requirement to 500hrs TIS for affected engines. The FAA contends that 3000 of the 3200 engines affected by this AD have already been inspected. Engines that were previously inspected under the priority letter AD are not required to conduct any additional inspections.

Related documents:

Letter from AOPA president Phil Boyer to TCM president Bryan Lewis, April 28, 1999

TCM Critical Service Bulletin CSB-99-3A Synopsis, April 1999

TCM Critical Service Bulletin CSB-99-3A, April 1999

TCM Critical Service Bulletin CSB 99-6A, July 21, 1999 (514k; requires Adobe Reader)

FAA Priority letter AD 99-09-17, April 22, 1999

AOPA News Release 99-2-028

Letter to AOPA president Phil Boyer from TCM president Bryan Lewis, May 13, 1999 (requires Adobe Reader)

AD 99-19-01, September 15, 1999