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TFE731 Inspection Intervals

January 2016

Duncan Aviation Tech Reps and Sales Reps field many questions regarding inspection intervals. Most often, these pertain to the newer model engines: TFE731-20/-40/-60 and the -5BR. Intervals for the -20/-40/-50/-60 models can be found in chapter five of the LMM 7 Ch 5-20-00 scheduled maintenance checks Table 801.

Engine Intervals

  • All -50 and -40BR-1B engines are 3000 MPI/6000 CZI intervals.
  • -20/-40/-60 engines are either 2500 MPI/5000 CZI or 3000 MPI/6000 CZI intervals, depending on the service bulletins that have been accomplished.
  • -40 and -60 engines will be on the 2500 MPI/5000 CZI intervals unless service bulletin 72-5194 has been completed. This SB had a limited release in December 2007 and full release in April 2008. There are several other bulletins that are part of the extension. If SB 72-5194 is not done, there is no need to look any further.
  • -20 engines engine serial number P-116487 and later will have all of the internal parts upgraded for the 3000 MPI/6000 CZI hour intervals. Some simple external bulletins may need to be complied with to make the interval extension official, such as checking the Fuel Control serial number and putting heat shrink on the N1 monopole. If you have any questions, please give us a call and we will help you clarify the intervals.

Classic Engines

In the case of classic engine models, the official answer is to reference the following Service Bulletins:


SB 72-3105

TFE 731-2C

SB 72-3630

TFE 731-3 & 3A

SB 72-3106

TFE 731-3B

SB 72-3233

TFE 731-3C & 3D

SB 72-3527

TFE 731-4

SB 72-3466

TFE 731-5R, 5AR, 5BR

SB 72-3263

The basic rules for these classic engines can be best explained as follows:

  • Almost all -2 and -3 engines that have not been upgraded to -2C/-3C/-3D are on 1400 MPI/4200 CZI intervals.
  • All -2C/-3C/-3D engines are on a 2100 MPI/4200 hour CZI schedule.
  • The -4/-5 engines are either 2100 MPI/4200 CZI or 2500 MPI/5000 CZI intervals, again depending on which service bulletins have been accomplished. If you have any questions, please call and we will clarify.

The MPI can be overrun by 100 hours and the CZI by 200 hours on all of these models of the TFE 731 engine.

Engine Component Life Limits

In addition to inspection intervals, TFE731 engines are impacted greatly by the life limits of the engine components within them. Read more about it here: Tracking Component Life Limits.