Airworthiness Directive · Amendment 39-14567 · General Electric Company CT64-820-4 Turboprop Engines
General Electric Company CT64-820-4 Turboprop Engines
This AD applies to General Electric Company (GE) CT64-820-4 turboprop engines that use any of the rotating parts listed in Table 1 of this AD. These engines are installed on, but not limited to, DeHavilland DHC-5D Buffalo airplanes.
| Rotor assembly | Part nomenclature | Part No. |
|---|---|---|
| Compressor | Shaft, Front | 5007T03P03 |
| Disk, Stage 1 | 5015T92P01 | |
| Retainer, Disk, Stage 1 | 5013T71P01 | |
| Disk, Stage 2 | 5015T93P01 | |
| Spacer, Disk, Stage 2 | 5015T94P01 | |
| Disk, Stage 3 | 5015T95P01 | |
| Spool, Rotor, Front | 6003T84P02 | |
| Spool, Rotor, Rear | 6005T18P01 | |
| Shaft, Rear | 6005T26P01 | |
| Gas Generator Turbine | Disk and Shaft, Stage 1 | 6014T70P02 |
| Disk, Stage 2 | 4007T83P02 | |
| Ring, Torque | 3008T60P02 | |
| Seal, Air, Stage 1 | 4007T94G02 | |
| Plate, Cooling | 3008T52P02 | |
| Plate, Cooling | 4022T37P01 | |
| Seal, Interstage | 5006T54P02 | |
| Seal, Air, Rear | 4022T36P01 | |
| Seal, Air, Rear | 4022T36P03 | |
| Power Turbine | Disk, Stage 3 | 4008T65P02 |
| Disk, Stage 4 | 5006T16P03 | |
| Disk, Stage 4 | 5006T16P04 | |
| Seal, Interstage | 4008T29P01 | |
| Shaft, Main | 5009T73P02 | |
| Shaft, Main | 6012T83P02 | |
| Tiebolt, Power Turbine Rotor | 3008T44P02 |
The FAA is adopting a new airworthiness directive (AD) for General Electric Company (GE) CT64-820-4 turboprop engines with certain part number (P/N) rotating parts. The parts are in the compressor rotor assembly, gas generator turbine rotor assembly, and power turbine rotor assembly that are subject to low-cycle fatigue. This AD requires removing from service these affected rotating parts at reduced compliance times. This AD results from the manufacturer's discovery of cracks in some rotating parts. We are issuing this AD to prevent cracks in the rotating parts that could cause compressor and turbine wheel fracture and uncontained engine failure. An uncontained engine failure could cause possible damage to the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
(h) If performing the actions required by this AD for “Data Fleet” engines, follow paragraphs (j) through (o).
(i) If performing the actions required by this AD for “No-Data Fleet” engines, follow paragraphs (p) through (u).
For parts listed in Table 3 of this AD and installed in serviceable engines (those that are in service or have met the requirements for and have been approved for return to service) on the effective date of this AD, do the following:
(1) If the cycles-since-new (CSN) of a part listed in Table 3 of this AD are equal to or more than Table 3, Limit 2 as of the effective date of this AD, remove the part before exceeding 900 additional cycles-in-service (CIS) or Table 3, Limit 1, whichever occurs first, but not later than July 31, 2013.
(2) If the CSN for a part listed in Table 3 of this AD are fewer than Table 3, Limit 2 as of the effective date of this AD, remove the part from service before exceeding Table 3, Limit 3, but not later than July 31, 2013.
| Rotor | Nomenclature | Part No. | Limit 1 (cycles) | Limit 2 (cycles) | Limit 3 (cycles) |
|---|---|---|---|---|---|
| Compressor | Shaft, Front | 5007T03P03 | 30,000 | 29,100 | 30,000 |
| Disk, Stage 1 | 5015T92P01 | 13,000 | 8,100 | 9,000 | |
| Retainer, Disk, Stage 1 | 5013T71P01 | 30,000 | 29,100 | 30,000 | |
| Disk, Stage 2 | 5015T93P01 | 23,000 | 8,100 | 9,000 | |
| Spacer, Disk, Stage 2 | 5015T94P01 | 30,000 | 8,100 | 9,000 | |
| Disk, Stage 3 | 5015T95P01 | 9,000 | 8,100 | 9,000 | |
| Spool, Rotor, Front | 6003T84P02 | 5,100 | 2,100 | 3,000 | |
| Spool, Rotor, Rear | 6005T18P01 | 19,000 | 3,500 | 4,400 | |
| Shaft, Rear | 6005T26P01 | 30,000 | 8,100 | 9,000 | |
| Gas Generator Turbine | Disk and Shaft, Stage 1 | 6014T70P02 | 7,000 | 6100 | 7000 |
| Disk, Stage 2 | 4007T83P02 | 11,300 | 5,400 | 6,300 | |
| Ring, Torque | 3008T60P02 | 30,000 | 6,100 | 7,000 | |
| Seal, Air, Stage 1 | 4007T94G02 | 30,000 | 11,700 | 12,600 | |
| Plate, Cooling | 3008T52P02 | 5,000 | 4,100 | 5,000 | |
| Plate, Cooling | 4022T37P01 | 5,000 | 4,100 | 5,000 | |
| Seal, Interstage | 5006T54P02 | 5,100 | 4,200 | 5,100 | |
| Seal, Air, Rear | 4022T36P01 | 5,000 | 4,100 | 5,000 | |
| Seal, Air, Rear | 4022T36P03 | 5,000 | 4,100 | 5,000 | |
| Power Turbine | Disk, Stage 3 | 4008T65P02 | 30,000 | 12,100 | 13,000 |
| Disk, Stage 4 | 5006T16P03 | 30,000 | 12,100 | 13,000 | |
| Disk, Stage 4 | 5006T16P04 | 30,000 | 12,100 | 13,000 | |
| Seal, Interstage | 4008T29P01 | 30,000 | 12,100 | 13,000 | |
| Shaft, Main | 5009T73P02 | 13,000 | 12,100 | 13,000 | |
| Shaft, Main | 6012T83P02 | 13,000 | 12,100 | 13,000 | |
| Tiebolt, Power Turbine Rotor | 3008T44P02 | 13,000 | 12,100 | 13,000 |
(k) For all rotating parts listed in Table 3 of this AD and put into service after the effective date of this AD, remove from service before the CSN exceeds Table 3, Limit 3, but not later than July 31, 2013.
(l) After the effective date of this AD:
(1) Do not install any part listed in Table 3 of this AD that has a CSN equal to or more than Table 3, Limit 3.
(2) If the CSN for a part listed in Table 3 of this AD are fewer than Table 3, Limit 3:
(i) Until July 31, 2007, you may return the part to service, if the part passes the applicable inspections specified in the CT64-820-4 Engine Overhaul Manual, SEI-448.
(ii) You must remove the part from service before Table 3, Limit 3 is exceeded, but no later than July 31, 2013.
(iii) After July 31, 2007, do not install any part listed in Table 3 of this AD.
(m) On July 31, 2007, for engines in service that have a part listed in Table 3 of this AD, remove the affected part before exceeding Table 3, Limit 3, but no later than July 31, 2013.
(n) For main shafts, P/N 5009T73P02, and P/N 6012T83P02, and power turbine rotor tiebolt, P/N 3008T44P02, with unknown CSN do the following:
(1) Assign each part a CSN value of 7,400 CSN as of the effective date of this AD and refer to Table 3 of this AD for removal requirements.
(2) Continue to track the parts starting from 7,400 CSN and remove from service as specified in paragraphs (j) through (n) of this AD, but no later than July 31, 2013.
(o) For rear air seal, P/N 4022T36P03, and power turbine stage 4 disk, P/N 5006T16P04, with unknown CSN, remove the part before exceeding 10 additional cycles, but no later than July 31, 2013.
For parts listed in Table 4 of this AD and installed in serviceable engines (those that are in service, or have met the requirements for and have been approved for return to service) on the effective date of this AD, do the following:
(1) If the CSN of a part listed in Table 4 of this AD are equal to or more than Table 4, Limit 2 as of the effective date of this AD, remove the part before exceeding 50 additional CIS or Table 4, Limit 1, whichever occurs first, but not later than July 31, 2013.
(2) If the CSN for a part listed in Table 4 of this AD are fewer than Table 4, Limit 2 as of the effective date of this AD, remove the part from service before exceeding Table 4, Limit 3, but not later than July 31, 2013.
(q) For all rotating parts listed in Table 4 of this AD and put into service after the effective date of this AD, remove from service before the CSN exceeds Table 4, Limit 3, but not later than July 31, 2013.
| Rotor | Nomenclature | Part No. | Limit 1 (cycles) | Limit 2 (cycles) | Limit 3 (cycles) |
|---|---|---|---|---|---|
| Compressor | Shaft, Front | 5007T03P03 | 30,000 | 29,950 | 30,000 |
| Disk, Stage 1 | 5015T92P01 | 13,000 | 8,950 | 9,000 | |
| Retainer, Disk, Stage 1 | 5013T71P01 | 30,000 | 29,950 | 30,000 | |
| Disk, Stage 2 | 5015T93P01 | 23,000 | 8,950 | 9,000 | |
| Spacer, Disk, Stage 2 | 5015T94P01 | 30,000 | 8,950 | 9,000 | |
| Disk, Stage 3 | 5015T95P01 | 9,000 | 8,950 | 9,000 | |
| Spool, Rotor, Front | 6003T84P02 | 5,100 | 2,950 | 3,000 | |
| Spool, Rotor, Rear | 6005T18P01 | 19,000 | 4,350 | 4,400 | |
| Shaft, Rear | 6005T26P01 | 30,000 | 8,950 | 9,000 | |
| Gas Generator Turbine | Disk and Shaft, Stage 1 | 6014T70P02 | 7,000 | 6,950 | 7,000 |
| Disk, Stage 2 | 4007T83P02 | 11,300 | 6,250 | 6,300 | |
| Ring, Torque | 3008T60P02 | 30,000 | 6,950 | 7,000 | |
| Seal, Air, Stage 1 | 4007T94G02 | 30,000 | 12,550 | 12,600 | |
| Plate, Cooling | 3008T52P02 | 5,000 | 4,950 | 5,000 | |
| Plate, Cooling | 4022T37P01 | 5,000 | 4,950 | 5,000 | |
| Seal, Interstage | 5006T54P02 | 5,100 | 5,050 | 5,100 | |
| Seal, Air, Rear | 4022T36P01 | 5,000 | 4,950 | 5,000 | |
| Seal, Air, Rear | 4022T36P03 | 5,000 | 4,950 | 5,000 | |
| Power Turbine | Disk, Stage 3 | 4008T65P02 | 30,000 | 12,950 | 13,000 |
| Disk, Stage 4 | 5006T16P03 | 30,000 | 12,950 | 13,000 | |
| Disk, Stage 4 | 5006T16P04 | 30,000 | 12,950 | 13,000 | |
| Seal, Interstage | 4008T29P01 | 30,000 | 12,950 | 13,000 | |
| Shaft, Main | 5009T73P02 | 13,000 | 12,950 | 13,000 | |
| Shaft, Main | 6012T83P02 | 13,000 | 12,950 | 13,000 | |
| Tiebolt, Power Turbine Rotor | 3008T44P02 | 13,000 | 12,950 | 13,000 |
(r) After the effective date of this AD:
(1) Do not install any part listed in Table 4 of this AD that has a CSN equal to or more than Table 4, Limit 3.
(2) If the CSN for a part listed in Table 4 of this AD are fewer than Table 4, Limit 3:
(i) Until July 31, 2007, you may return the part to service, if the part passes the applicable inspections specified in the CT64-820-4 Engine Overhaul Manual, SEI-448.
(ii) You must remove the part from service before Table 4, Limit 3 is exceeded, but no later than July 31, 2013.
(iii) After July 31, 2007, do not install any part listed in Table 4 of this AD.
(s) On July 31, 2007, for engines in service that have a part listed in Table 4 of this AD, remove the affected part before exceeding Table 4, Limit 3, but no later than July 31, 2013.
(t) For main shafts P/N 5009T73P02, and P/N 6012T83P02, and power turbine rotor tiebolt, PN 3008T44P02, with unknown CSN, remove the part before exceeding 50 additional cycles
(u) For rear air seal, P/N 4022T36P03, and power turbine stage 4 disk, P/N 5006T16P04, with unknown CSN, remove the part before exceeding 10 additional cycles, but no later than July 31, 2013.
(v) For all engines, calculate the cycles remaining on the affected rotating parts and make an entry in the Engine Log Book marked with the engine S/N and its fleet category, either “DATA FLEET” or “NO-DATA FLEET.”
(1) Date and file the record in the Engine Log Book.
(2) Note in the Engine Log Book that AD 2006-08-10 has been complied with.
