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88-14-01: 88-14-01 TEXTRON LYCOMING (FORMERLY AVCO LYCOMING TEXTRON): Amendment 39- 5952. Applies to Textron Lycoming LTS101 series turboshaft engines.
Compliance is required as indicated, unless already accomplished.
To prevent an uncontained failure of the power turbine (PT) disk, which could result from failure of the Number 3 or Number 4 bearings, accomplish the following:
(a) Visually inspect all chip detectors, rate the amount and type of debris, and determine the category and type of chip light event, prior to further flight, in accordance with TEXTRON Lycoming Service Bulletin (SB) LT 101-77-30-0104, Revision 1, dated March 18, 1988, and accomplish the requirements of the Accomplishment Instructions, paragraph II.E., and II.F. of the SB, whenever the debris monitor cockpit indicator light that is wired to the rear bearing support housing (RBSH) and/or the airframe mounted full flow scavenge debris monitor is illuminated.
(b) Check, each day of operation, the continuity of the RBSH scavenge debris monitor, if so configured, and the full flow scavenge debris monitor cockpit indication light system(s) by removing the monitor(s), shorting the magnetic contacts, and ensuring that the cockpit indication light(s) illuminates. If the light does not illuminate, correct the condition prior to further flight.
NOTES: (1) Refer to the appropriate aircraft maintenance manual for corrective action.
(2) FAA approved RBSH and full flow scavenge debris monitor indication light systems which permit the continuity to be checked from the aircraft cockpit, coupled with other appropriate checks, may be approved as an equivalent means of compliance to this paragraph by the Manager, Engine Certification Office, Federal Aviation Administration, New England Region.
(c) Check the engine oil pump output pressure as follows within 50 hours in service after receipt of priority letter AD 87-10-10, issued May 15, 1987, or priority letter AD 86-22-08, issued October 30, 1986,otherwise within 50 hours in service after December 23, 1987, and immediately following an oil pump change and whenever oil pressure adjustment is required. If an engine oil pump output pressure check has been accomplished in accordance with the requirements of priority letter AD 87-10-10 R1, issued June 16, 1987, or priority letter AD 86-22-08, and documentation does not exist verifying that the pump output pressure was set at a value within the revised range given in the table of paragraph (c)(3) below, accomplish this check, as set forth below, within 50 hours in service after December 23, 1987.
(c) (1) Install a tee fitting in the line connecting the oil pressure transmitter to the engine oil pump, and install a direct reading wet pressure gauge (any gauge ranging from 0 - 125 up to 200 psig, calibrated to plus/minus 2.0 percent at 100 psig) and an orifice of 0.025 inches in the line between the tee fitting and the wet pressure gauge.
CAUTION: Ensure that the orifice is installed in the line between the tee fitting and the wet pressure gauge and not in the oil pressure supply line to the engine.
(c) (2) Start the engine and warm the oil to 150 degrees Fahrenheit minimum. Increase the gas producer speed (Ng) to 95 percent. Stabilize at this Ng for at least one minute.
(c) (3) Adjust the engine oil pressure, in accordance with the table given below, by removing the lockwire from the slotted oil pressure adjustment slug on the right side of the oil pump and filter housing assembly, and turning the slug clockwise to increase pressure or counterclockwise to decrease pressure (one turn equals approximately 15 (psig). If, prior to the above adjustment, the engine oil pump pressure indicated 70 psig or less for the LTS101-750 series engines, or 58 psig or less for the LTS101-600 and -650 series engines, prior to further flight, disassemble the RBSH assembly and inspect the Number 2 and Number 3 bearings and associated components.
ENGINE MODEL
SPECIFIED RANGE
LTS101-600A-2/-650B-1/-650B-1A/-650C-2/-650C-3/-650C-3A/-750B-1/-750C-1
80-100 psig
LTS101-600A-3/-750B-2
90-100 psig
NOTE: Refer to the appropriate engine maintenance manual instructions.
(c) (4) Verify that the aircraft oil pressure indicator indicates in the green arc when the oil pump is properly adjusted. If, upon completion of the check, the aircraft pressure gauge does not indicate in the green arc, the aircraft indicating system must be checked and corrected.
NOTE: Refer to the appropriate aircraft maintenance manual instructions.
(c) (5) Remove the wet gauge, orifice, and tee fitting, and reconnect the oil pressure transmitter.
(c) (6) Ensure that the slotted oil pressure adjustment slug is lockwired after proper adjustment.
NOTE: Accomplishment of the oil pump output pressure check at new production engine acceptance testing or at installation of new production engines by the engine or aircraft manufacturer, respectively, is considered an equivalent means of compliance with the requirement of the above paragraph for the initial check within 50 hours in service.
(d) Conduct an oil acidity check in accordance with the procedure given in the appropriate engine maintenance manual, Chapter 71-00-00, as follows:
(d) (1) Check the oil acidity within 25 hours in service after receipt of priority letter AD 87-10-10 or priority letter AD 86-22-08, otherwise within 25 hours in service after December 23, 1987, or within 50 hours in service since the last oil change, whichever occurs later, and repeat at intervals not to exceed 25 hours in service until the oil pump filter and engine oil are changed.
(d) (2) Thereafter, perform an initial oil acidity check within 50 hours in service after the oil pump filter and engine oil are changed, and repeat at intervals not to exceed 25 hours in service until the oil pump filter and engine oil are changed.
(d) (3) If the oil acidity check limit, as specified in the appropriate engine maintenance manual, Chapter 71-00-00, is exceeded, prior to further flight, flush the engine lubrication system (including airframe- supplied oil cooler, tank, lines, etc.) and change the oil pump filter and engine oil.
NOTES: (1) Refer to the appropriate engine maintenance manual instructions.
(2) Information regarding the availability of approved acidity test kits may be obtained by contacting TEXTRON Lycoming, LT101 Product Support.
(e) Visually inspect the Number 4 power pinion gear roller bearing for cage cracks or metal release within 25 hours in service after receipt of priority letter AD 87-12-11, issued June 16, 1987, otherwise within 25 hours in service after December 23, 1987, by removing the Np indicator cover from the front of the gearbox.
(e) (1) If the cage is cracked or any metal is evident in the bearing area, prior to further flight, disassemble the gearbox to correct the condition.
(e) (2) If no cracking or metal release is noted, reinstallthe Np indicator cover.
NOTES: (1) Removal and installation of the Np indicator cover should be accomplished in accordance with the appropriate engine maintenance manual and Avco Lycoming TEXTRON Maintenance Alert Notice, MA-LTS-101-72-00-0015, Revision 1, dated September 5, 1986.
(2) Inspection of the Number 4 bearing at new production engine assembly by the engine manufacturer is considered an equivalent means of compliance with the above requirement for engines with no time in service upon receipt of priority letter AD 87-12-11, otherwise as of December 23, 1987.
(f) Visually inspect the RBSH scavenge debris monitor, if so configured, otherwise inspect the full flow scavenge debris monitor, within 50 hours in service after December 23, 1987, and thereafter, at intervals not to exceed 50 hours in service since last inspection, for metal contamination. If metal debris of sufficient quantity to illuminate the debris monitor cockpit indication light is evident on the respective debris monitor, prior to further flight, accomplish the requirements of paragraph (a) above pertaining to debris monitor light illumination.
NOTE: Individual chips, flakes, slivers, granules, splinters, or fuzz accumulation of sufficient dimension to bridge the magnetic contacts and illuminate the debris monitor cockpit indication light, though it has not done so prior to this repetitive inspection, are also cause for rejection. Metal of insufficient quantity to illuminate the debris monitor cockpit indication light is acceptable and may be cleaned from the debris monitor upon completion of this repetitive inspection.
(g) Following assembly of an engine in which the PT module was built-up with a used RBSH and/or a used oil feed ring, conduct a post-build engine run-up and inspect the RBSH assembly in accordance with step 1.7 of Avco Lycoming TEXTRON Commercial Service Letter (CSL) 047, dated October 10, 1986, prior to return to service. If a clogging inspection value of 2.5 psig is exceeded, clean and inspect the RBSH and oil feed ring in accordance with steps 1.1 through 1.7 of Avco Lycoming TEXTRON CSL 047, dated October 10, 1986, or in accordance with SB LT 101-72-40-0103, dated January 15, 1988.
NOTES: (1) Compliance with the requirements of TEXTRON Lycoming SB LT 101-72-40-0103, dated January 15, 1988, is considered an equivalent means of compliance to the post-build engine run-up and inspection requirements of this paragraph.
(2) Accomplishment of a clogging inspection of the Number 2 and Number 3 bearing oil jets, prior to RBSH disassembly, may be advantageous under certain conditions. Refer to the appropriate engine maintenance manual instructions.
(h) If the type of oil is changed, conduct a clogging inspection of the Number 2 and Number 3 bearing oil jets in accordance with the procedure given in the appropriate engine maintenance manual, Chapter 79-30- 00 for LTS101-600A-2/ 600A-3/-750A-1 engines and Chapter 72-00-00 for the remaining LTS101 engine models, not less than 5 hours and not to exceed 10 hours in service after the oil change. If the clogging inspection limit of 5.0 psig is exceeded, accomplish paragraph (j) below.
(i) If at any time, excluding initial engine oil pump installation, the pump output pressure is or was adjusted downward, prior to further flight, conduct a clogging inspection of the Number 2 and Number 3 bearing oil jets in accordance with the procedure given in the appropriate engine maintenance manual, Chapter 79-30-00 for LTS101-600A-2/-600A-3/-750A-1 engines and Chapter 72-00-00 for the remaining LTS101 engine models. If the clogging inspection limit of 5.0 psig is exceeded, accomplish paragraph (j) below.
(j) If the limit for the clogging inspection of the Number 2 and Number 3 bearing oil jets of 5.0 psig is exceeded during accomplishment of paragraph (h) or (i) above, or during accomplishment of the applicable TEXTRON Lycoming engine maintenance manual periodic clogging inspection requirement, prior to further flight, accomplish the following:
(j) (1) Disassemble the RBSH assembly to correct the cause of clogging, and inspect the Number 2 and Number 3 bearings and associated components.
NOTE: Refer to the appropriate engine maintenance manual instructions.
(j) (2) Clean and inspect the RBSH and oil feed ring in accordance with Avco Lycoming TEXTRON CSL 047, dated October 10, 1986, or in accordance with the requirements of TEXTRON Lycoming SB LT 101- 72-40-0103, dated January 15, 1988.
NOTE: Any time the clogging inspection results of the Number 2 and Number 3 bearing oil jets are recorded to document compliance with paragraph (g), (h), (i), or (j) of this AD, it is recommended that the actual gauge Number 2 value be recorded in the engine logbook.
(k) Aircraft may be ferried in accordance with the provisions of FAR 21.197 and 21.199 to a base where the AD can be accomplished.
(l) Upon request, an equivalent means of compliance with therequirements of this AD may be approved by the Manager, Engine Certification Office, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803.
(m) Upon submission of substantiating data by an owner or operator, through an FAA Airworthiness Inspector, the Manager, Engine Certification Office, New England Region, may adjust the compliance schedule specified in this AD.
TEXTRON Lycoming SB LT 101-77-30-0104, Revision 1, dated March 18, 1988, TEXTRON Lycoming SB LT 101-72-40-0103, dated January 15, 1988, and Avco Lycoming TEXTRON CSL 047, dated October 10, 1986, identified and described in this document are incorporated herein and made a part hereof, pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to TEXTRON Lycoming, Williamsport Division, LT101 Product Support, 654 Oliver Street, Williamsport, Pennsylvania 17701. These documents also may be examined at the Office of the Regional Counsel, Federal Aviation Administration, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803, Rules Docket Number 86-ANE-39, Room 311, between the hours of 8:00 a.m. and 4:30 p.m., Monday through Friday, except federal holidays.
This amendment, 39-5952, supersedes Amendment 39-5787 (52 FR 48187; December 21, 1987), AD 87-26-10.
This amendment, 39-5952, becomes effective on July 6, 1988.
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