JT15D Engines Summer 2000
- Engine Windmilling
- If Lightning Strikes, Double Check Your Engine
- Pratt & Whitney Service Bulletin 7437
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Engine Windmilling
Questions often come up regarding the effect of engine windmilling and whether or not maintenance actions are required if it has occurred. Following is a guide to windmilling situations and actions required. Consult the appropriate Pratt & Whitney maintenance manual for maintenance procedures:
A. Engine windmilling on ground: No action required.
B. If engine windmilling in flight does not exceed 15 minutes: No action required.
C. If engine windmilling in flight exceeds 15 minutes:
- WITH positive oil pressure indication: No action required.
- WITHOUT positive oil pressure indication:
- a) Inspect oil filter element per maintenance manual.
- b) Perform engine ground run checks and inspect the oil and fuel filters following ground runs. If fuel pump outlet filter is contaminated, change fuel pump only.
- WITH fuel shut off or no fuel boost pressure:
- a) Remove fuel pump outlet filter element and check for contamination.
- b) Check fuel pump per the maintenance manual.
- c) Check the fuel filter elements following fuel pump check. If contaminated, replace fuel pump.
For more info, contact Ken Kuchenreuther in BTL at 800.525.2376 or Doug Alleman in LNK at 800.228.4277.
If Lightning Strikes, Double Check Your Engine
Summertime is the season for lightning strikes on airplanes. If you suspect your aircraft has been subjected to a lightning strike, a visual inspection of the engine inlet is required. If evidence of arcing (pitting, black scarring) is present on the inlet cone or LP Compressor (Fan) blades, remove engine from service.
Return the engine to an approved overhaul facility for lightning strike Special Conditions inspection in the appropriate Overhaul Manual.
For more info, contact Ken Kuchenreuther in BTL at 800.525.2376 or Doug Alleman in LNK at 800.228.4277.
Pratt & Whitney Service Bulletin 7437
Pratt & Whitney has introduced SB 7437. This SB replaces the Bleed Valve and Impeller Housings on JT15D-5/-5A/-5B/-5C and -5F engines with applicable serial numbers during engine overhaul. Complying with this SB replaces the bleed linkage with a new arrangement that eliminates the links and pads and introduces a roller guide that reduces the actuating force needed to move the bleed valve system. This necessitates replacing the bleed valve housing and impeller housing with new components having revised bosses. A seal between the bleed valve housing and the bleed valve liner is introduced to improve engine performance by reducing the air leakage.
These changes require the replacement of the liner with a new thicker liner having a groove to accept the seal. The new bleed valve housing will also have a thinner front rim to accommodate the thicker liner. Estimated cost to comply with this recommended SB at overhaul is $35,000.
For more info, contact Ken Kuchenreuther in BTL at 800.525.2376 or Doug Alleman in LNK at 800.228.4277.
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