Par 7-196 Page 7-357 TABLE 7-13. (CONTINUED) N u tP a r tN u m b e r Description NAS395-396 Nut, U type NAS443 Nut, self-locking, int. wrenching NAS444-445 Nut, double lug, anchor type, offset NAS446 Nut, flat type NAS447-448 Nut, plate, self-locking NAS449 Nut, anchor type NAS450 Nut, plate, self-locking NAS463 Shim, plain anchor nut NAS487 Nut, instrument mount NAS500 Shim, anchor nut, csk.
NAS509 Nut, drilled
TABLE 7-13. (CONTINUED) N u tP a r tN u m b e r Description NAS577-578 Nut, self-locking floating barrel retainer NAS671 Nut, plain hex., small pattern NAS680-681 Nut, plate, self-locking, two lug NAS682-683 Nut, plate, self-locking, one lug NAS684-685 Nut, plate, corner, self-locking NAS686 Nut, plate, self-locking, two lug, floating NAS687 Nut, plate, self-locking, one lug NAS688-695 Nut Assembly, self-locking, gang channel NAS696 Nut, plate self-locking, one lug, miniature NAS697 Nut, plate, self-locking, two lug, miniature NAS698 Nut, plate, corner, self-locking, miniature
Par 7-196 Page 7-358 TABLE 7-13. (CONTINUED) N u tP a r tN u m b e r Description NAS1021-1022 Self-locking Nut, hex., regular and low ht.
NAS1023-1024 Nut, plate, self-locking, two lug NAS1025-1026 Nut, plate, self-locking, one lug NAS1027-1028 Nut, plate, corner, self-locking NAS1029-1030 Nut, plate, self-locking, one lug, two lug NAS1031 Nut, plate, self-locking, two lug, floating NAS1032 Nut, plate, self-locking, one lug, floating NAS1033 Nut, plate, right angle, floating, self-locking NAS1034-1041 Nut Assembly, self-locking, gang channel NAS1067 Nut, plate, self-locking, one lug, miniature NAS1068 Nut, plate, floating, self-locking, two lug, miniature
TABLE 7-13. (CONTINUED) N u tP a r tN u m b e r Description NAS1098 Nut, tube fitting NAS1287-1288 Nut, hexagonal, self-locking, nut and washer shear pin NAS1291 Nut, hexagonal, self-locking, low height NAS1329 Nut, blind rivet, flathead, internal thread NAS1330 Nut, blind rivet, csk. Head, internal thread NAS1408-1409 Nut, hexagonal, self-locking, regular height, coarse and fine thr.
NAS1410 Nut, tube fitting NAS1423 Nut, plain, thin hex., drilled jamnut NAS1473 Nut, plate, self-locking, two lug, cap floating NAS1474 Nut, plate, self-locking, two lug, cap floating, reduced rivet spacing NAS1512-1513 Nut, plate, self-locking gang channel
Par 7-196 Page 7-359 TABLE 7-13. (CONTINUED) N u tP a r tN u m b e r Description NAS8679 Nut, self-locking, low height 550 °F, 800 °F
TABLE 7-14. TABLE OF WASHERS.
Washer Number Description AN935 Washer, lock, spring AN936 Washer, tooth lock AN950 and 955 Washer, ball socket, ball seat AN960 Washer, flat AN961 Washer, flat electrical (Brass, silver or tin-plated) AN970 Washer, flat, wood AN975 Washer, flat AN8013 Washer, insulator AN122576-122600 Washer, plain steel TABLE 7-14. (CONTINUED) Washer Number Description MS9081 Washer, key dbl.
Bearing retaining MS9274 Washer, key, dbl.
Bearing ret. Cres.
MS9276 Washer, key, cres.
AMS 5510 180° locking MS9320-9321 Washer, flat AMS 6350 and 5510 MS9482 Washer, flat, steel AMS 6437 or AMS 6485 diffused nickel cad.
Csk MS9549 Washer, flat, AMS 5510 MS9581 Washer, key, cres.
AMS 5510 90° locking MS9582 Washer, key, cres. AMS 5510 270° locking MS9684 Washer, cup, lock cres. AMS 5510 MS9768 Washer, flat, cres. AMS 5525 and AMS 5737 csk.
MS9880 Washer, cup, lock cres.
AMS 5510
Par 7-196 Page 7-360 TABLE 7-14. (CONTINUED) Washer Number Description MS9952 Washer, cup, lock, spanner nut, cres.
AMS 5646 MS15795 Washer, flat, metal MS17811 Washer, thrust, steel MS19069-19070 Washer, key, retaining MS20002 Washer, plain, csk., hi-strength MS21258 Washer, key, retaining, steel MS25081 Washer, key MS27051 Washer, slotted MS27111 Washer, finishing, countersunk MS27129 Washer, finishing, csk., 80°, 82° MS27183 Washer, flat, round
TABLE 7-14. (CONTINUED) Washer Number Description MS28777 Washer, hydraulic, packing backup MS35333-35334 Washer, lock, flat internal tooth, light and heavy MS35335-35336 Washer, lock, flat and csk., external tooth MS35337-35340 Washer, lock, med., light, heavy MS35790 Washer, lock, 100° csk., ext. tooth MS122026-122075 Washer, lock spring MS172201-172235 Washer, key, single bearing, retaining MS172271-172320 Washer, key, single NAS70 Washer, plain NAS143 Washer, csk. and plain NAS390-391 Washer, finishing
Par 7-196 Page 7-361 TABLE 7-14. (CONTINUED) Washer Number Description NAS460 Washer, tab type NAS513 Washer, rod end locking, steel NAS549 Washer, flat, resin fiber NAS620 Washer, flat, reduced O.D.
NAS1061 Washer, hi-temp, lock, spring NAS1099 Washer, bevel 9 1/2° NAS1169 Washer, dimpled 100° NAS1197 Washer, flat, 5052 aluminum NAS1252 Washer, flat NAS1401 Washer, radius, al.
Alloy, steel, cres. Steel NAS1515 Washer, plastic and rubber
TABLE 7-14. (CONTINUED) Washer Number Description NAS1587 Washer, 1200 °F, plain and csk.
NAS1598 Washer, sealing NAS1636 Washer, key dual tab NAS1640 Washer, lock, spring, nonmagnetic
TABLE 7-15. TABLE OF PINS.
Pin Number Description AN253
Pin, hinge AN380 & 381 Pin, cotter AN385 Pin, plain taper AN386 Threaded taper pin AN392-406 Pin, flathead AN415 Pin, lock
Par 7-196 Page 7-362 TABLE 7-15. (CONTINUED) Pin Number Description AN416
Pin, retaining safety AN122676-122775
Pin, dowel steel AN121601-121925 Pin, flathead clevis .125 -.500 drilled shank AN150201-150400 Pin, lock, steel, brass MS9047 Pin, spring, steel, phoshated finish
MS9048 Pin, spring, steel, cadmium plate MS9105 Pin, lock MS9164 Pin, straight, steel, headless, oversize MS9245 Pin, cotter, cres. AMS 7211 MS9389 Pin, straight, headless, lock, AMS 5735 MS9390 Pin, straight, headless, cres. AMS 5735, dowel std. & O.S.
TABLE 7-15. (CONTINUED) Pin Number Description MS9462-9468 Pin, straight hd. AMS 5735 MS9486 Pin, straight, headless, lock, AMS 5132 MS9842-9848 Pin, straight, headed, AMS 5616 MS16555 Pin, straight, headless .0002 over nominal size MS16556 Pin, straight, headless .001 over nominal size MS16562 Pin, spring, tubular, slotted MS17984-17990 Pin, quick release, positive lock MS20253
Pin, hinge MS20392 Pin, straight, headed, drilled MS24665 Pin, cotter MS35671-35679 Pin, grooved, headless, tapered groove
Par 7-196 Page 7-363 TABLE 7-15. (CONTINUED) Pin Number Description MS35810 Pin, clevis, headed MS39086 Pin, spring, tubular coiled MS51923 Pin, spring, tubular coiled MS51987 Pin, tubular coiled MS171401-171900 Pin, spring, SS, steel NAS427 Pin, pulley guard, steel, al. Alloy NAS561 Pin, spring slotted and coiled, heavy duty NAS574 Pin, rear mounting NAS607 Pin, headless, dowel, steel NAS1292-1296 Pin, shear thread 100° flush head NAS1322 Pin, shear thread, protruding head
TABLE 7-15. (CONTINUED) Pin Number Description NAS1332-1346 Pin, quick release NAS1353-1366 Pin, quick release, positive locking, double acting NAS1407 Pin, spring, coiled NAS1436-1442 Pin, swage lock, 100° shear head, pull type, steel NAS1446-1452 Pin, swage lock, protruding head, pull type, steel NAS1456-1462
Pin, swage lock, 100° head, pull type, steel NAS1465-1472
Pin, swage lock, protruding head, pull type, steel NAS1475-1482
Pin, swage lock, 100° head, pull type, steel NAS1486-1492 Pin, swage lock, 100° head, stump type, steel NAS1496-1502 Pin, swage lock, protruding head, stump type, steel NAS1525-1532 Pin, swage lock, protruding head, al. alloy
Par 8-1 Page 8-364 TABLE 7-15. (CONTINUED) Pin Number Description NAS1535-1542
Pin, swage lock, 100° hd., tension, pull type, alum.
NAS1546-1552
Pin, swage lock, 100° hd., tension, stump type, alum.
NAS1583
Pin, 100° csk. hd., hi-shear rivet, 1200 °F NAS1584
Pin, flathead, hi-shear rivet, 1200 °F
7-196.7-206. [RESERVED.]
Par 8-1 Page 8-365 CHAPTER 8. ENGINES, FUEL, EXHAUST, AND PROPELLERS
SECTION 1. ENGINES
GENERAL. Consult the manufacturer’s manuals, service bulletins, and instruction books regarding the repair and overhaul, inspection, installation, and maintenance of aircraft engines, for that particular make, model, and type of engine. This section lists acceptable inspection and repair procedures that may be used in the absence of an engine manufacturer’s maintenance information.
SPECIAL INSPECTION. A visual inspection is needed to determine the condition of the engine and its components. An annual or 100-hour inspection should include the engine and nacelle group as follows.
Cold Cylinder Check. If an engine is running rough the cause may be a bad ignition lead, a spark plug not firing, a partially clogged fuel injector, or a bad magneto. The dead cylinder will be colder than the surrounding cylinders and can be quickly determined by using the recommended cold cylinder checks. This should be done using a thermocouple probe which is very sensitive to small differences in temperature, which is the case with a partially-clogged injector. For a carbureted engine, the following check may be helpful:
Using experienced personnel, run the engine on the bad magneto for approximately 30 seconds at 1200 rpm. Without switching the magneto switch back to both shut off the engine. Have another mechanic use a grease pencil (non-carbon), and quickly mark each exhaust stack approximately 1 inch from the flange that holds the exhaust stack to the cylinder. Next, check the exhaust stacks and look for the exhaust stack whose grease pencil mark has not turned to a grayish-white or ash color. This is the cold cylinder.
The probable cause of the cold cylinder is either a defective spark plug or ignition lead.
Switch spark plugs to another cylinder and run the test again. If the problem stays with the original cylinder, the problem is either the ignition lead or the magneto.
Piston Engine Sudden Stoppage Inspection. Sudden stoppage is a very rapid and complete stoppage of the engine. It can be caused by engine seizure or by one or more of the propeller blades striking an object in such a way that rpm goes to zero in less than one complete revolution of the propeller. Sudden stoppage can cause internal damage to constant-speed propellers; reduction drive; gear train damage in the accessory section;
crankshaft misalignment; or damage to accessories such as magnetos, generators, vacuum pumps, and tach generators.
Every engine that suffers a sudden stoppage must be inspected in accordance with the manufacturer’s maintenance instructions before being returned to service.
If the engine manufacturer does not provide the required information, then the engine case must be opened and every major component part must be inspected using visual and/or nondestructive inspection (NDI) procedures as applicable.
The sudden-stoppage inspections include:
checking for cowling, spinner, and airframe cracks and hidden damage; and alignment of the engine mount to the airframe,
Par 8- Sec 1 Page 366 the mounting hardware, isolation mounts, and bushings.
The aircraft’s firewall must also be checked for distortion, cracks, and elongated bolt holes. The damaged propeller must be sent to an FAA-certificated repair station for complete NDI and repair.
Engine accessories such as: magnetos, starters, fuel pumps, turbochargers, alternators, or generators must be inspected in accordance with the manufacturer’s maintenance manual on sudden stoppage or overhaul procedures to determine the product’s airworthiness.
Reciprocating Engine (Direct Drive). Preliminary inspection before tear down.
Remove the engine cowling and examine the engine for visible external damage and audible internal damage.
Rotate the propeller shaft to determine any evidence of abnormal grinding or rubbing sounds.
With the propeller removed, inspect the crankshaft flange or splines for signs of twisting, cracks, or other deformation.
Remove the thrust-bearing nut and seal and thoroughly inspect the threaded area of the shaft for evidence of cracks.
Rotate the shaft slowly in 90-degree increments while using a dial indicator or an equivalent instrument to check the concentricity of the shaft.
Remove the oil sump drain plug and check for metal chips and foreign material.
Remove the oil screens and inspect for metal particles and contamination.
Visually inspect engine case exterior for signs of oil leaks and cracks. Give
Par 8- Sec 1 Page 367 particular attention to the propeller thrustbearing area of the nose case section.
Inspect cylinders and cylinder hold-down area for cracks and oil leaks. Thoroughly investigate any indication of cracks, oil leaks, or other damage.
Internal Inspection Requirements.
On engines equipped with crankshaft vibration dampers, remove and inspect the cylinders, and inspect the crankshaft dampers in accordance with the engine manufacturer’s inspection and overhaul manual. When engine design permits, remove the damper pins, and examine the pins and damper liners for signs of nicks or brinelling.
After removing the engine-driven accessories, remove the accessory drive case and examine the accessory and supercharger drive gear train, couplings, and drive case for evidence of damage.
Check for cracks in the case in the area of accessory mount pads and gear shaft bosses.
Check the gear train for signs of cracked, broken, or brinelled teeth.
Check the accessory drive shaft couplings for twisted splines, misalignment, and runout.
Check connecting rods for cracks and straightness.
Reciprocating Engine (Gear-Drive). Inspect the engine, propeller, (refer to section 4 on propeller inspection), and components as described in the preceding paragraphs.
Remove the propeller reduction gear housing and inspect for:
Par 8-2 Page 8-368 Loose, sheared, or spalled cap screws or bolts.
Cracks in the case.
Disassemble the gear train and inspect the propeller shaft, reduction gears and accessory drive gears for nicks, cracks, or spalling.
Engine-Mount Inspection.
Examine the engine flex mounts when applicable, for looseness of engine to mount, distortion, or signs of wear.
Inspect the engine-mount structure for bent, cracked, or buckled tubes.
Check the adjacent airframe structure firewall for cracks, distortion, or wrinkles.
Remove engine-mount bolts and mount holddown bolts and replace.
Exhaust-driven Supercharger (Turbo) Inspection. Sudden stoppage of the powerplant can cause the heat in turbine parts to heatsoak the turbine seals and bearings. This excessive heat causes carbon to develop in the seal area and varnish to form on the turbine bearings and journals.
Inspect all air ducts and connections for air leaks, warpage, or cracks.
Remove compressor housing and check the turbine wheel for rubbing or binding, and coke or varnish buildup.
NOTE: Turbine turbo supercharger disk seal rubbing is not unusual and may be a normal condition. Consult the engine manufacturer’s inspection procedures and table of limits.
Accessory and Drive Inspection. Check the drive shaft of each accessory, i.e., magnetos, generators, external superchargers, and pumps for evidence of damage.
CRANKSHAFT INSPECTION AND REPAIR REQUIREMENTS. Carefully inspect for misalignment and replace if bent beyond the manufacturer’s permissible service limit. Worn journals may be repaired by regrinding in accordance with manufacturers’ instructions.
It is recommended that grinding operations be performed by appropriately-rated repair stations or the original engine manufacturer.
Common errors that occur in crankshaft grinding are the removal of nitrided journal surface, improper journal radii, unsatisfactory surfaces, and grinding tool marks on the journals. If the fillets are altered, do not reduce their radii. Polish the reworked surfaces to assure removal of all tool marks. Most opposed engines have nitrided crankshafts, and engine manufacturers specify that these crankshafts must be re-nitrided after grinding.
NOTE: Rapid deceleration or momentary slowing of a propeller may occur due to contact with tall grass, water, or snow. If this occurs, the engine and propeller should be inspected in accordance with the manufacturer’s instruction or service bulletins.
REPLACEMENT PARTS IN CERTIFICATED ENGINES. Engine replacement parts must be approved under Title 14 of the Code of Federal Regulations (14 CFR), part 21. Serviceable parts obtained from the engine manufacturer, authorized service facility, and those which are approved Federal Aviation Administration (FAA)/Parts Manufacture Approval (PMA), or Technical Standard Order (TSO), and meet the requirements of part 21 are acceptable for use as replacement parts. Used engine parts can be installed