Airworthiness Directive · Amendment 39-19063 · Turbine section
Honeywell International Inc. Turbofan Engines
Superseded. A later AD replaced this one: AD 2018-21-01. Comply with the one in force.
This AD applies to Honeywell International Inc. (Honeywell) AS907-1-1A turbofan engines with second stage low-pressure turbine (LPT2) rotor blades, part number (P/N) 3035602-1, installed.
We are adopting a new airworthiness directive (AD) for certain Honeywell International Inc. (Honeywell) AS907-1-1A turbofan engines. This AD was prompted by reports of loss of power due to failure of the second stage low-pressure turbine (LPT2) blade. This AD requires a one- time inspection of the LPT2 blades and, if the blades fail the inspection, the replacement of the blades with a part eligible for installation. We are issuing this AD to address the unsafe condition on these products.
(1) For LPT2 rotor blades, P/N 3035602-1 that have more than 8,000 hours since new on the effective date of this AD, perform a one-time borescope inspection for wear of the Z gap contact area at the blade tip shroud for each of the 62 LPT2 rotor blades within 200 hours time in service after the effective date of this AD.
(2) Use the Accomplishment Instructions, Paragraph 3.B.(1), of Honeywell Service Bulletin (SB) AS907-72-9067, Revision 1, dated March 20, 2017, to do the inspection.
(3) If the measured wear and/or fretting of any Z gap contact area is greater than 0.005 inch, replace the LPT2 rotor assembly with a part eligible for installation before further flight.
(4) Do the following actions within 200 hours time in service after the effective date of this AD:
(i) Using a borescope make a clear digital image of the Z gap contact area at the blade tip shroud of the 62 LPT2 rotor blades.
(ii) Identify the three Z gap contact areas with the greatest amount of wear and/or fretting.
(iii) Record the blade position on the LPT2 rotor assembly and the measured wear of the three Z gap contact areas with the greatest amount of wear and/or fretting.
(iv) Send the results to Honeywell at engine.reliability@honeywell.com within 30 days after completing these actions.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Engines
