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Airworthiness directives › 2012-02-07

AD 2012-02-07 Airworthiness Directives; General Electric Company Turbofan Engines

Superseded. This directive was replaced by AD 2023-04-11. Work to the current one.
2012-03-06
2012-01-31
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Engine
2023-04-11

Applicability*9

This AD applies to General Electric Company (GE) CF6-45A, CF6-45A2, CF6-50A, CF6-50C, CF6-50CA, CF6-50C1, CF6-50C2, CF6-50C2B, CF6-50C2D, CF6-50E, CF6-50E1, CF6-50E2, and CF6-50E2B turbofan engines, including engines marked on the engine data plate as CF6-50C2-F and CF6-50C2-R, with any of the low-pressure turbine (LPT) rotor stage 3 disk part numbers listed in Table 1 of this AD installed. Table 1—Applicable LPT Rotor Stage 3 Disk Part Numbers           9061M23P06 9061M23P07 9061M23P08 9061M23P09 9224M75P01 9061M23P10 1473M90P01 1473M90P02 1473M90P03 1473M90P04 9061M23P12 9061M23P14 9061M23P15 9061M23P16 1479M75P01 1479M75P02 1479M75P03 1479M75P04 1479M75P05 1479M75P06 1479M75P07 1479M75P08 1479M75P09 1479M75P11 1479M75P13 1479M75P14 N/A N/A N/A N/A

Compliance

For the BSIs required by paragraphs (f)(1), (f)(2), and (f)(3) of this AD, inspect the blades from the forward and aft directions. Inspect all areas of the blade airfoil. Your inspection must include blade leading and trailing edges and their convex and concave airfoil surfaces. Inspect for signs of impact, cracking, burning, damage, or distress. (1) Perform an initial BSI of the HPT rotor stage 1 and stage 2 blades within 10 cycles after the effective date of this AD. (2) Thereafter, repeat the BSI of the HPT rotor stage 1 and stage 2 blades within every 75 cycles since last inspection (CSLI). (3) Borescope-inspect the HPT rotor stage 1 and stage 2 blades within the cycle limits after the engine has experienced any of the events specified in Table 2 of this AD. (4) Remove any engine from service before further flight if the engine fails any of the BSIs required by this AD. Table 2—Conditional BSI Criteria If the engine has experienced: Then borescope-inspect: (i) An exhaust gas temperature (EGT) above redline. Within 10 cycles. (ii) A shift in the smoothed EGT trending data that exceeds 18 °F (10 °C), but is less than or equal to 36 °F (20 °C) Within 10 cycles. (iii) A shift in the smoothed EGT trending data that exceeds 36 °F (20 °C) Before further flight. (iv) Two consecutive raw EGT trend data points that exceed 18 °F (10 °C), but is less than or equal to 36 °F (20 °C), above the smoothed average Within 10 cycles. (v) Two consecutive raw EGT trend data points that exceed 36 °F (20 °C) above the smoothed average Before further flight.

Required actions

For those engines that fail any BSI requirements of this AD, before returning the engine to service: (1) Remove the LPT rotor stage 3 disk from service; or (2) Perform a fluorescent-penetrant inspection (FPI) of the inner diameter surface forward cone body (forward spacer arm) of the LPT rotor stage 3 disk as specified in paragraphs (l)(1)(i) through (l)(1)(iii) of this AD.

Unsafe condition

Comply with this AD within the compliance times specified, unless already done.

Affected ADs

This AD supersedes AD 2011-02-07, Amendment 39-16580 (76 FR 6323, February 4, 2011) and AD 2011-18-01, Amendment 39-16783 (76 FR 52213, August 22, 2011).

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