Modifications, Maintenance & Repairs |
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Note- all bold print items represent modifications from the original aircraft configuration Mods, Repairs, and Maintenance to Twin Comanche N8121Y Careful inspection of logbooks prior to my purchase of aircraft revealed that both engines were top-overhauled at 684 tach time in May 1979 and both prop blades on both engines were replaced in 1971 per Hartzell service bulletin. All other maintenance appeared regular and routine. Very careful inspection of this aircraft revealed no damage history or signs of repair. Note---engine oil and oil filters are always replaced at each annual inspection and on many occasions in between. July 19, 1989 Purchased Twin Comanche N8121Y Tach Time and Total Time on Airframe: 789 hours August 1989 Engine starters both rebuilt Permanently removed 5th and 6th seats and associated seat belts for insurance purposes. October 1989 We did a major rebuild of avionics panel as well as a general refurbishing of airplane: We kept the King KNS-80 RNAV and KT-76A transponder, the Narco AR-500 encoder, and the KMA 20 audio panel, but almost everything else was changed out: We added: KR-87 ADF with KI 229 slaved ADF readout KX-155 NAV-COM with KI 209 glide slope indicating head KY 97A COM radio KCS 55A HSI S-TEC 60-2 Autopilot with altitude pre-select and new turn & bank Astrotec clock/timer WX 10A Stormscoope Apollo Model 618 Loran PS Engineering intercom dual type with rear seat isolation Davtron pressure altitude readout Davtron DVOR PTT on both yokes Westbend timer on pilot yoke Electric trim on yoke New 1/4 inch aluminum instrument-avionics panel (one piece) Dual master avionics switches Dual tachometer replaces two separate ones Handheld radio jack in panel Input jack for cassette player Avionics cooling fan Replaced flap indicator Replaced VSI and Manifold Pressure Gauge All 4 fuel bladders reconditioned Rebuilt R Bendix fuel servo Both fuel selector valves reconditioned New copper cables from battery to starters and aux power plug to replace aluminum Installed strobes on wingtips Re-sealed both aux fuel pumps Replaced one fuel level transmitter New oil and fuel line hoses in both engine compartments New floor insulation New door locks- Ace tubular key type Replaced door seal around cabin door Airplane weighed with new wt and bal Installed new Rosen type sunvisors New fuel selector decals New fuel door latch Replaced L cowl flap cable, adjusted R one Replaced all engine compartment hoses both engines made by Aviall Installed loran to autopilot coupling Installed external airswitch to Hobbs meter Rebuilt "whiskey" compass with new gaskets New Airspeed indicator Rebuilt prop governor in L engine April 1990: Dynamic prop balance at Byam Propeller shop New battery Replaced mirror on L engine cowling Replaced Southco fasteners on nose cowling with nutplates May 1990: Annual Inspection Replaced generator brushes both sides Replaced brake discs and pads Replaced sparkplugs all 8 cylinders Replaced Timken bearings in nose gear wheel Replaced air filters both engines Replaced L main gear brake line " L main gear door hinge " Oil and filters both sides " scat tubing L generator " R Lord engine mounts Rotated L engine mounts Cleaned and gapped plugs Timed magnetos Replaced Zerc fitting in nose gear (grease nipple) Replaced L landing light bulb November 1990 Replaced carpet, sidewalls, curtains, and upholstery of seats Removed Apollo 618 Loran and installed Northstar M1A Loran March 1991 Replaced generators both engines with Interav alternators, regulators, and over-voltage relays in addition to circuit breakers Repaired (welded) exhaust stack on R engine June 1991 Annual Inspection Installed new fuel selector decals Replaced ELT battery Replaced push rod tube O rings and seals, oil return line hoses, rocker box cover silicone gaskets, Replace fuel door latches Replaced brake O rings Installed Hobbs meter on Janitrol Heater Heater AD inspection Replaced brake discs with Flite Life black stainless discs and organic pads Replaced nose wheel shimmy dampener with new rebuildable model made by Parker-Hannafin Overhauled landing gear transmission Repaired (welded) alternate air box R engine and installed new bell crank kit Repaired (welded) exhaust stack #4 cylinder Left engine Replaced nose gear tire January 1992 Annual Inspection Installed new exhaust hanger hoses Installed new bungee cords both main landing gear Replaced nose gear canvas tent Replaced various bolts and bushings in landing gear per inspection for AD Replaced boot on nose wheel steering rod Installed Piper Kit 761-082 on nose gear Replaced both main gear tires Replace cylinder head temp probe on L engine May 1992 Replaced Davtron 903 Unit with model 903 ID-Z s/n 2796 Replaced Davtron Model 630 with Model M655 s/n 3972 Purchased Kennon Heat Shields for aircraft August 1992 Replaced all 4 magnetos with New Slick Model 4373 Magnetos and wiring harnesses Replaced engine driven fuel pumps both engines Lycoming LW15473 Replaced all spark plugs both engines with Champion REM40E type plugs Replaced bushing in R starter housing MZ298 bushing March 1993 Annual Inspection Replaced prop governor oil lines and installed steel fittings, c/o AD 90-04-06 Replaced both front crankshaft seals, prop O rings and alternator belts Replaced air filters both engines Replaced battery Replaced Lord engine mounts L engine Replaced brake pads both main gear Cleveland 66-105 pads Installed Strike Finder Weather avoidance system and removed StormScope Installed Northstar M2 Loran/GPS Unit, removed Northstar M1A IFR certification for altimeter and transponder April-May 1994 Annual Inspection Replace Vacuum Pump R Engine Repaired R exhaust manifold with installation of ball joint modification by A/C Exhaust Systems in W.Va Replaced diaphragms in both fuel manifold blocks June 1994 Replaced display in KNS 80 April 1995 Annual Inspection Replaced R starter Bendix Repaired Air Filter Box R Engine Repaired Alternate Air Box L Engine Replaced both air filters Replaced ELT battery Replaced L over-voltage relay Added two standoff steel brackets for fuel injection lines per AD 93-02-05 (two per engine) June 1995 IFR certification of altimeter and transponder August 1995 Heater decay test to comply with AD April 1996 Annual Inspection Replaced Luggage Door Strut with new design by Knots 2 U Complied with SB 518 Lycoming thermostatic valve inspection Replaced bungee cords on both main landing gear Replaced cushion material in pilot seat May 1996 Overhauled Attitude Indicator Replace existing ELT with installed Ameri-King model 450 in same location using same antenna and cable March 1997 Replaced battery in remote Northstar GPS unit April 1997 Annual Inspection Replaced Vacuum Pump L Engine Replaced EGT gauge with Alcor dual EGT gauge model 46125 October 1997 Replaced battery with new Gill G-35 Battery December 1997 Heater decay test to comply with AD May 1998 Annual Inspection Re-swung “whiskey” compass May 1999 Annual Inspection Rebuilt Nose wheel strut with new O rings, etc. Replaced R and L Main gear tires with 6.00X6 6 ply rated Custom Goodyear Tires Installed new brake pads both main gear 66-10 organic Cleveland pads Installed remote ELT switch in panel Replaced landing gear bungee cords both main gear Overhaul L prop due to oil leak Replaced Vacuum pump L engine Replace Fuel lines both engines Replaced L alternator belt December 1999 Update on Y2K issues with Northstar GPS February 2000 IFR certification of transponder and static system June 2000 Heater decay test per AD at Brodie’s Aircraft in Fort Worth July 1, 2000 Annual Inspection Replaced Schraeder Valve in nose gear oleo strut Replaced EGT probe on L engine Replaced Air Filters both engines WIX 42040 Replaced vacuum regulator filter L engine Replaced Lord engine mounts R engine August 1, 2000 Repaired #4 cylinder L engine, new exhaust valve, seat, guides, piston, rings. Note- on return trip from Colorado, it was noted that the compression was low on that cylinder while hand-turning the prop to circulate oil. Exhaust valve stem was noted to be corroded and tolerance was very loose in the guides. All other cylinders had good compression. August 10, 2000 Installed exhaust extensions on both engines Replaced internal battery in Navigator M2 Loran August 20, 2000 Replaced #3 cylinder R engine with re-built chrome cylinder assembly in Louisville, KY after noting engine running rough on landing. The plane was then flown back to Grand Prairie, TX. August 31, 2000 On disassembling cylinder, it was found that exhaust valve had broken off and had been ingested by cylinder, damaging the piston and cylinder head. Therefore it was elected to replace/repair the remaining cylinders on both engines. All cylinders were removed and inspected. Three cylinders were found to be in good condition and therefore those 3 were put on the L engine after replacing the rings, exhaust valves, seats, and guides. Replaced all cylinders on R engine with rebuilt chrome cylinder assemblies Replaced L EGT probe October 10, 2000 Overhauled both fuel injection controller servos June 20, 2001 Repaired left engine exhaust manifold with ball joint by A/C Exhaust Systems of Jumping Branch, W.Va. Weld repair of left engine cowling crack which occurred when exhaust manifold broke and hit inside of cowling. August 31, 2001 Annual Inspection- packed wheel bearings, serviced brakes, new Janitrol heater AD complied with Repaired broken field wire to R alternator Replaced brush block on R alternator Replaced panel gear indicator lights with press-to-test type lights September 5, 2002 Annual Inspection Replaced Gill G-35 Battery Replaced both bungee cords Replaced both starter drives Replaced ELT batteries (6 D cells expire March 2008) Replaced brake pads, O rings in slave cylinders, both sides Rebuilt brake master cylinders with new O rings, etc., both sides Cleaned fuel strainers, replaced gaskets, and O rings in sump drains Cleaned finger screens in fuel injector servos Replaced Garlok seal in vacuum pump drive Adjusted idle mixture in Left engine Repaired both air filter box covers Cleaned and gapped spark plugs Repacked wheel bearings Placarded Heater controls inoperative to avoid AD inspection (had very mild winter) Repaired hinge on "clam shell" of right engine cowling. October 1, 2003 Annual Inspection Replaced all engine hoses, including flexible fuel and oil hoses. 500 hour inspection of all 4 magnetos, including lubrication, and re-setting internal timing Flushed and pressure tested left oil cooler due to left engine running hotter than right Replaced all cowling screws with stainless steel screw kit Replaced both induction air filters Replaced all spark plugs on both engines. Rebuilt right brake master cylinder with new O rings. Repaired another hinge on "clam shell" of right engine cowling. Changed oil and replaced oil filters both engines. Adjusted idle and idle mixture on left fuel injector servo. Cleaned belly of plane and under wings behind engines with industrial grade detergent. November 14, 2003 Replaced roll servo in S-Tec autopilot with factory rebuilt servo at Tomlinson Avionics, Gainesville, TX. November 1, 2004 Annual Inspection Drained and replaced engine oil and oil filters both engines. Rebuilit left main gear brake master cylinder. Replaced O rings in left fuel drain sump. December 15, 2005 Annual Inspection Changed oil and replaced oil filters both engines. Changed bungee cords on landing gear. Inserted spacer washers between engine and lower Lord mounts on right engine to raise engine slightly. Recommended by Maurice Taylor to raise engine even after new Lord mounts will not raise engine to proper position in cowling due to age of engine mounts, etc. Replaced Garlock seal and both gaskets on vacuum pump on right engine. Replaced no-blow gasket on left engine #2 cylinder. Replaced O rings in both main gear slave cylinders and rebuilt left master cylinder. Replaced brake pads on both main gear. November 1, 2006 Annual Inspection Due to a rough running right engine, found #4 exhaust valve stuck. Subsequently checked all valve guide clearances and reamed three exhaust valve guides. Replaced landing gear side brace stud (AN26-25) and main side brace stud bushing on left main gear. Replaced both main gear tires and tubes. Cleaned battery box and painted inside with acid resistant paint. Removed prop governor on left engine and replaced with overhauled unit from Quality A/C Accessory in Tulsa. Installed new cabin door hinge pins. Installed new lug on P lead to right magneto on right engine. Changed oil and replaced oil filters both engines. Cleaned belly of plane and under wings behind engines with industrial grade detergent. Replaced one spark plug on #4 cylinder on right engine which failed pressure testing. Feb 12, 2007 Static and Transponder Check for IFR flight March 31, 2007 Removed #3 cylinder on Right Engine for overhaul due to low compression May 12, 2008 Annual Inspection Changed oil and replaced oil filters both engines. Installed new lug on right magneto of Right Engine. Replaced D cell batteries in ELT. Next replacement due 2011. March 12, 2010 Annual Inspection Performed Landing Gear AD 77-13-21 totally disassembled landing gear, measured all bolts and bushings, drag link ends and bearing rod ends. Installed new AN 178-40 and AN 6-26 bolts on left side of nose gear linkage. Fabricated new steering arm roller bushings. Installed new bungees on both main gear. Performed retraction load test with torque tube adaptor and torque wrench. Found less than 95 pounds required which is well within tolerance. Greased all Zirc fittings on landing gear after reassembly. Inserted new hinge pins in main landing gear doors. Stop-drilled three small cracks in left main gear door near hinge. Fabricated and installed a 3 nut plate aluminum strip on each side to replace the three #10 nuts which attach the main gear doors to the wing. Had both nose gear doors repainted at GLO A/C Paint at Northwest Regional Airport. Performed AD 97-01-01-R1: removed both main gear side brace studs and had both magnaflux and dye tested for cracks at Apex Lab in Addison, TX. No cracks found. Repaired and reinstalled nose gear blanket. Repainted battery box with acid resistant paint on inside and flat black enamel on the outside. Stripped and treated nose section fore of the wheel well with Alodine and painted with primer. Replaced all battery drain hoses. Removed, repaired, and reinstalled battery drain assy. Installed new Gill G-35 battery. Installed new Rapco brake disks on both main gear, P/N RA 164-02201. Replaced brake pads and both flexible brake lines. Bled brakes. Replaced landing gear wiring harnesses and switches. Weight and balance not affected. Rebuilt both fuel strainers using new gaskets, O-rings, and drain hoses. Per AD 96-09-10, on both engines, removed all accessories and rear accessory case and replaced oil pump housing assy P/N 00SL78528, gear kit P/N 00AEL18109-S, and oil pump drive shaft P/N 00AEL61174. Reinstalled all accessories with new gaskets.. Compression check Right engine: (1) 78/80 (2) 75/80 (3) 79/80 (4) 78/80. Left engine: check (1) 79/80 (2) 77/80 (3) 76/80 (4) 78/80. Replaced engine driven fuel pump on left engine P/N LW 15473 and gasket. Timing reset to 25 degrees BTC on both mags on both engines. Heater reconnected and determined to be in airworthy condition. Performed Heater Pressure Decay Test per AD 04-21-05. Heater passed test. ELT battery exp date 2011. |
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