Cherokee 08F has returned from her very thorough 100hr inspection. I apologize to the Cherokee pilots who were caught by both weather and maintenance over the last 3 weeks. 08F will be going to Cable for some additional radio work sometime in the next week, but she is ready to fly again after a brief hiatus.
Cessna 08V has returned from the engine shop. She had a new alternator installed and an oil leak found and fixed.
Cessna 72F will be taken down this week in order to effect a conversion to key-start. We're fed up with the pull starter. :)
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It occurs to me that some of you (particularly Cherokee pilots) are wondering what is involved in a 100hr inspection, and what the big deal is all about. I often throw the phrase around like it's a routine thing, because for us, it is -- however, it is quite an involved process that you should understand and appreciate.
FAR Part 91.409(b) states, among lots of other gibberish:
no person may give flight instruction for hire in an aircraft which that person provides, unless within the preceding 100 hours of time in service the aircraft has received an annual or 100-hour inspection and been approved for return to service in accordance with part 43 of this chapter
Part 43 details the mechanic's responsibility for logging airframe repairs, but let me describe for you a little about what is involved in an actual 100-hour inspection.
The minimum time any 100-hour will take is appx 16 hours' labor. That's if there are no squawks. Some planes have great 100hr inspections, and sometimes, there are more than a normal amount of things to fix. A typical 100hr squawk list is about 20 items which need replacing or repair. This month, Cherokee 08F had 37 items -- hence the unusually long 100hr.
Say what you want about the FAA -- I think the 100hr inspection is an excellent way to ensure that the Aircraft remain flying and in great condition. It is due to the stringent maintenance and the "graceful failure" engineering in our aircraft that any developing problems always remain small and manageable, even in-flight.
I laugh when I see car dealerships advertising "70-point inspections" -- I present to you our "appx every month 205-point aircraft inspection" Next time you see that car broken down in the fast lane on the 91 freeway, marvel at the following things we do every 100 flight hours:
The Fly Corona! 100-hour inspection
Stage I: Flight runup
- Check Fuel Pump Pressure
- Check Oil Pressure
- Check Oil Temp
- Check Voltage/Charging System
- Check Parking Brake Operation
- Check Vacuum Pressure
- Listen for Gyro noise/whine in Gyro instruments
- Verify operation of Cabin Environmental Controls
- Verify Magneto Switch Operation
- Record Mag Drops (L & R)
- Check Throttle Cable Operation
- Check Mixture Cable Operation
- Check Carburetor Heat Cable Operation
- Note Engine Idle
- Check Avionics Operation
Stage II: Engine
- Remove Engine Cowling
- Clean and Inspect Cowling for Damage
- Drain Oil
- Change Oil Filter
- Install new Oil Filter
- Inspect Oil Temperature Probe for leaks/ill fitting
- Inspect oil cooler lines and fittings for leaks, security, chafing dents, and cracks.
- Clean and inspect oil cooler fins
- Fill engine with 8 US quarts Aero Shell 15W50 oil.
- Clean engine – CAUTION – do not contaminate vacuum pump with cleaning solution
- Check condition of spark plugs. Clean and adjust air gap as required
- Inspect spark plug cable leads and ceramics for corrosion and deposits
- Check cylinder compression
- Reinstall spark plugs – torque to 360 – 420 ”/lbs (30 – 35 ‘/lbs)
- Check cylinders for cracked or broken fins
- Inspect rocker box covers for leaks. Remove covers every 400 hours and check per note 12
- Inspect magneto points for condition and proper clearance 018” ± .006”
- Inspect for Oil leaks
- Inspect breaker felts for lubrication
- Inspect distributor block for cracks, burned areas, or corrosion and height of contact springs
- Check timing - light on 25° BTDC
- Clean air filter – NOTE: If filter is K&N clean per instructions
- Drain Carburetor and clean inlet strainer
- Inspect condition of carb heat air box and door
- Inspect vent lines for fuel leaks and clamps for tightness
- Inspect all induction hoses – replace as needed
- Inspect condition of all flexible fuel lines. Replace at Engine TBO or as required
- Inspect fuel system for leaks. Replace rubber fuel tank vent hoses every 1000 hours.
- Clean screen in electric fuel pump and re-safety
- Clean filter bowl and re-safety
- Inspect vacuum pump and hoses.
- Inspect throttle, mixture, carb heat cables for security, travel, and condition
- Inspect exhaust system
- Inspect engine breather tube for obstructions and security
- Inspect crankcase for cracks, leaks, and security of seam bolts
- Inspect engine mounts for crack and loose mountings
- Inspect engine baffles
- Inspect all wiring connected to engine or accessories
- Inspect firewall seals
- Inspect condition and tension of alternator belt
- Inspect condition of starter and alternator
- Lube starter bendix drive
- Inspect security of starter and alternator mounting
- Check brake fluid reservoir
- Lubricate all engine controls
- Reinstall cowl
Stage III: Propeller
- Inspect Propeller back plate
- Inspect blades for nicks or cracks
- Inspect spinner mounting brackets
- Inspect Propeller mounting bolts and safety wire
- Reinstall Spinner
Stage IV: Cabin
- Inspect cabin entrance, door, and windows for damage and operation
- Remove seats, carpet, plates, and panels
- Inspect seats, seat belts, and seat tracks
- Check trim operation
- Inspect rudder pedals
- Inspect parking brake handle for operation and cylinder for leaks
- Inspect control wheels, column pulleys and cables
- Inspect flap handle and cable attach bolt
- Inspect cabin, navigation, landing, pulse, and instrument lights
- Inspect pitot/static instruments, lines, and attachments – See SB 582
- Inspect gyroscopic instruments
- Replace air pump filter at annual
- Replace regulator filter at annual
- Inspect Altimeter. Check IFR Cert
- Check operation of the fuel selector valve.
- Inspect condition of heater controls and ducts
- Inspect condition and operation of air vents
Whew... halfway there!
Stage V: Fuselage
- Remove inspections plates and panels
- Inspect battery, box and cables
- Inspect electronic installation
- Inspect bulkheads and stringers for damage
- Inspect antenna mounts and electric wiring
- Inspect ELT
- Proper installation
- Battery Corrosion
- Operation of the controls and crash sensor
- Sufficient signal
- Battery due date
- Inspect aileron, rudder, stabilator, stabilator trim cables, turnbuckles, guides, and pulleys for safety, damage, and operation
- Check all cable tensions
- Aileron 40 ± 5
- Flap 10 ± 1
- Stabilator 40 ± 5
- Stabilator trim 14 ± 1
- Rudder 40 ± 5
- Inspect fuel lines, valves, gauges for damage and operation
- Inspect vertical fin and rudder for damage
- Inspect rudder hinges, horn and attachments for damage and operation
- Inspect rudder control stop to insure stop has not loosened and locknut is tight
- Inspect vertical fin attachments
- Inspect rudder hinge bolts for excessive wear
- Inspect stabilator surfaces for damage
- Inspect stabilator, tab hinges, horn and attachments for damage and operation
- Inspect stabilator control stops to insure stop has not loosened and locknut is tight
- Inspect stabilator attachments.
- Inspect stabilator and tab hinge bolts and bearings for wear
- Inspect stabilator trim mechanism
- Clean and lubricate trim drum screw
- Lubricate all control system moving parts
- Inspect Vertical fin strobe for operation and security
- Reinstall plates and panels
Stage VI: Wings
- Remove inspection plates, panels, and fairings
- Inspect surfaces and tips for damage, loose rivets, and condition of walkway
- Inspect aileron hinges and attachments
- Inspect aileron control stops to insure stop has not loosened and locknut is tight
- Inspect aileron cables, pulleys, and bell cranks for damage and condition
- Inspect flaps and attachments for damage and operation
- Inspect condition of bolts used with hinges – replace as required
- Lubricate per lubrication chart in Piper Service Manual
- Inspect wing attachment bolts and brackets. Replace flexible fuel lines at engine overhaul
- Inspect fuel tanks and lines for leaks and water contamination
- Fuel tanks marked for capacity
- Fuel tanks marked for minimum octane rating
- Inspect fuel vents. Replace flexible lines at engine overhaul
- Inspect all air ducts, electrical leads, lines and attaching parts for security, routing, chafing, deterioration, wear, and correct installation
- Reinstall inspection plates and fairings
Stage VII: Landing Gear
- Inspect oleo struts for proper extension per Piper Service Manual – 3” minimum
- Inspect oleo struts for fluid leaks and scoring
- Inspect nose gear steering control for travel
- Jack aircraft
- Inspect tires for cuts, uneven or excessive wear and slippage
- Remove wheels
- Clean and repack wheel bearings
- Inspect wheels for cracks, corrosion, broken bolts
- Check pressure
- Inspect brake lining and disk for condition and wear
- Inspect brake backing plates for condition and wear
- Inspect brake lines
- Inspect shimmy dampener
- Inspect gear forks for damage
- Inspect gear struts, attachments, torque links, and bolts for condition and security
- Reinstall wheels
- Remove a/c from jacks
- Lubricate all moving components
- Inspect wheels for alignment
Stage VIII: Paperwork & Certification
- Aircraft conforms to FAA Specification
- All latest FAA Airworthiness Directives complied with
- All Manufactures Service bulletins complied with
- Check for proper flight manual
- Aircraft papers in order (AROW documents)
Stage IX: Squawks
- Repair or replace all items not found to be airworthy
- Sign Airframe & Engine Logbooks noting all work completed
- Return Aircraft to service.
...whew!
We do these inspections very routinely, and I think it is worth the time of every pilot to see one in action, or even assist if possible. If you are interested in seeing the innards of your favorite plane, drop me a line and let me know. Since the process is very laborious, if you would like to volunteer to get dirty with our mechanics, we credit $7.50/hr in flight time for assisting us with 100hrs. Don't worry -- only FAA-certified mechanics are allowed to put things ON the aircraft -- but there is plenty of screwdriver and scrub-brush work that goes on, which anyone can do.
Let me know if you'd like to learn AND get a little dirty AND get flight time credit in the process. I guarantee healthy amounts of all 3! :)
Blue (if soggy) Skies!
- Mike
