SERVICE BULLETIN M20-308A

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MOONEY AIRPLANE COMPANY, INC. SERVICE BULLETIN 165 Al Mooney Road Kerrville, Texas 78028 MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com Page 1 of 9 THIS BULLETIN IS FAA APPROVED FOR ENGINEERING DESIGN SERVICE BULLETIN M20-308A Date: December 19, 2008 SUBJECT: Mooney M20TN Aircraft Heater Enhancement for Extreme Cold Weather Operations MODELS/ SN Mooney M20TN Acclaim and Type-S Aircraft (31-0001 thru 31-0127) AFFECTED: TIME OF At Owners Discretion COMPLIANCE: INTRODUCTION: Mooney Airplane Company and Teledyne Continental Motors (TCM) have enhanced the de- sign of the heater for M20TN Acclaim and S-Type models. The enhanced design balances the heater performance more evenly across the engine power band and is targeted at aircraft operating in extreme cold weather conditions. Mooney Airplane has developed a retrofit kit for such operation. INSTRUCTIONS: Read entire procedures before beginning work. The purpose of this retrofit is to install an upgrade to the M20TN cabin heat system developed for aircraft operating in extreme cold weather conditions. The incorporation of this heater up- grade does not affect engine operation. The POH/AFM will require a revised Section VII to be inserted as part of this installation. STEP 1 - Duct Modification (only for Serial Numbers 31-0001 thru 31-0029) NOTE: The pilot seat and rear passenger seat need to be removed to allow access to side panel. 1.1. Turn master switch - OFF. 1.2. Remove pilot side lower interior panel retaining screws, and lower panel. 1.3. Remove pilot side upper interior panel mounting screws and slide upper panel towards rear to access 640328-505 duct assembly. 1.4. Locate 640328-505 duct assembly under and forward of instrument panel on left hand side of fuselage skin. 1.5. Locate and cut a 0.75” hole in the 640328-505 duct assembly as depicted in Figure M20-308-1. 1.6. Install 640328-11 deflector with (3) 1691-0410 Avex rivets on bottom as depicted in Figure M20-308-1. 1.7. Re-install pilot side upper and lower interior panels and hardware. STEP 2 - Heater Retrofit NOTE: The M20TN Type-S may skip steps 2.19, 2.20, 2.21 and 2.22, 640326--511 butterfly assembly is already installed. 2.1. Turn master switch - OFF. 2.2. Remove cowling per instructions provided in Chapter 71-10-00 of applicable MAC aircraft Service & Maintenance Manual. MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com Page 2 of 9 2.3. Modify AFT baffle by locating, marking and cutting a 1.65” diameter hole as depicted in Figure M20-308-2 2.4. Clean and debur edges on 1.65” diameter hole as required. 2.5. Match drill and use 1/8” rivets thru 912052-1 flange and AFT baffle (typ 3 places) (refer to Figure M20-308-2). 2.6. Remove existing heater box assembly by removing the (4) AN3-4A mounting bolts, remove and clean old sealant from surface of firewall area (refer to Figure M20-308-3). 2.7. Remove scat tubing and clamps from engine/firewall. 2.8. Remove existing exhaust crossover tube: (this may require 2 people) a.) Remove Right hand side retaining hardware (see Figure M20-308-4). Note: When removing RH side retaining hardware, keep tie rod bushing for re-assembly. b.) Remove upper and lower wastegate mounting hardware hardware (refer to Figure M20-308-4). c.) Remove LH transfer tube assembly from crossover tube, pull aft from turbo transition assembly and pull to out of crossover tube. d.) Remove crossover tube from RH transfer assembly aft and toward the right hand side. 2.9. Cover existing exhaust transfer tubes to prevent any foreign object debris (FOD) contamination into the exhaust system. 2.10. Remove any transfer tube covers to prevent (FOD), clean slip joints with scotchbrite and apply a high temp anti-seize lubricant before installation. NOTE: Before installing new crossover tube, make sure the (2) welded tabs have adequate clearance for inserting the tie rod and bushing assembly to slide into (refer to Figure M20-308-4). 2.11. Install new TCM P/N 657586 crossover tube and heater shroud in reverse order as described in steps 2.8. a.) Before installing the LH transfer tube assembly, replace both upper and lower wastegate gaskets P/N 652456 into recessed area of wastegate (refer to Figure M20-308-4). 2.12. Install new retention hardware P/N AN3-4A Bolt and MS21043-3 locknut and previously removed bushing, torque hardware in accordance with TCM engine maintenance instruc- tions (75-80 in. lbs.). 2.13. Install new lower wastegate mounting hardware (4) P/N MS20034-5 bolts, (4) NAS1587-4 washers, (4) MS20500-428 locknuts, do not torque, but leave allowable movement for upper hardware to be installed. 2.14. Install new upper wastegate mounting hardware (4) P/N MS20034-5 bolts, (4) NAS1587-4 washers, (4) MS20500-428 locknuts in place. Make sure there is no binding, then snug mounting hardware. Torque all lower and upper mounting hardware evenly in accordance with TCM engine maintenance instructions (240-280 in lbs.) (refer to Figure M20-308-4). 2.15. Install P/N 640335-511 cabin heater box assembly with existing hardware and gasket. If necessary replace heater box gasket with new P/N 640224-000 gasket. Seal edges against firewall with Pro Seal 700. 2.16. Install P/N 640231-501 silencer assembly using FLX770112001100 sleeve and (2) 20024 clamps. 2.17. Install remaining scat tube and clamps as depicted in Figure M20-308-5. MOONEY AIRPLANE COMPANY, INC. 165 Al Mooney Road, Kerrville, Texas 78028 tel: 830-896-6000 www.mooney.com Page 3 of 9 2.18. Check heater box cable rigging limits as depicted in Figure M20-308-6. NOTE: Type--S Acclaims may skip steps 2.19, 2.20, 2.21 and 2.22, 640326--511 butterfly assembly is already installed. 2.19. Inside of cabin, remove one end of 912007-503 flexible duct as location “A” as depicted in Figure M20-308-6.