Airworthiness and inoperative equipment
1st Lt Michael A. K. GrossPalo Alto Squadron 10, CAP2017
DREX at Oakland, normal taxi and run-upExtensive delay for takeoff due to training MO, mission request to stop on runway, and landing trafficTrim not checked immediately prior to takeoffNormal acceleration, rotation at 55 unsuccessful due to excessive control pressuresTakeoff aborted, left runway, trim observed full nose downDisabled electrical trim with AP circuit breaker, reset trim, took off againRequired pilot analysis indicated no possibility of recurrence with CB pulledCAWG ruled this a 14 CFR 91.213(d) violation with no risk to crew or equipment
For Part 91 piston aircraft, not allowed UNLESS:Equipment not required by14 CFR 91.205 (A TOMATO FLAMES, etc.),Aircraft certification,Airworthiness directives, orAircraft operating handbook or placardsEquipment is disabled or removed and placardedPilot in command determines flight can be accomplished safely
Equipment required by regulation, day VFR
Anticollisionlighting (aircraft newer than 1993)TachometerOil temperature gauge (air cooled engines)Manifold pressure gauge(not for naturally aspirated engines – but see KOEL for 182T)Airspeed indicatorTemperature gauge(not for air cooled engines)Oil pressure gauge (if oil is pressurized)Fuel gauges for each tankLanding gear position indicator(not for fixed gear)AltimeterMagnetic CompassEmergency location transmitter (with a few rare exceptions)Seat belts and shoulder harnessesFloatation gear (for hire out of gliding distance from land)Transponder (certain areas or IFR)
Equipment required by regulation, night VFR
All day VFR equipment, plusFuses(182Ts don't have any that can be changed in flight)Landing light (for-hire operations)Anticollisionlights (aircraft newer than 1971)Position lights (red, green, white)Source of power adequate for operation
Equipment required by regulation, IFR
All day and night VFR equipment, plusGenerator or alternator of adequate capacityRate of turn indicator (gyroscopic turn coordinator)Adjustiblesensitive altimeterBall (slip/skid indicator)Clock with second display (digital or analog)Attitude indicatorRadio and navigation suitable for route of flightDirectional gyroDME or GPS(above FL240; above service limit for 182T)
Other required equipment for G1000 182T
None required by airworthiness directivesNone required by type certification not described in POHKinds of Operation Equipment List has some additionsG1000 pilots reference guideTwo avionics fansMain battery and ammeterFlap motor and indicatorElevator and rudder trim and indicatorsElectric fuel pumpAlternate static and air induction (IFR only)Stall warningSystem annunciationsVarious interior and instrument lights (night only)Standby attitude indicator, airspeed indicator and altimeter (IFR only)Vacuum system and indicator (IFR only)Manifold pressure and fuel flow indicatorsCylinder head temperature gaugeOil dipstick
So, something doesn't work. What now?14 CFR 91.213(d)
For small piston aircraft operated under Part 91:Check regulationsCheck type (TCDS) and airworthiness directives on FAA websiteCheck Kinds of Operation Equipment List in POHDeactivate or removePlacardReview for safe operationIf you do ALL of these things and theinopequipment is not required, it is legal to take off
Traps and pitfalls
Removal from aircraftFAA allows removal of some simple types of systems by pilotsMust be logged, and specifically listed as "preventive maintenance" in Part 43 Appendix AMust use established procedures in maintenance manualAircraft must be reweighed if not replacedCAP does not allow this.Per CAPR 66-1, only a licensed and insured aircraft mechanic may remove systems.Autopilots, transponders, and DME units are explicitly excluded from "preventative maintenance" and are not removeable by pilots.
Traps and pitfalls, part 2
Disabling equipmentVery badly understood in community; conflicting data from FAA and othersAC 91-67 says systems can be disabled by turning a switch off, but makes a confusing double-negative prohibition on actions that are not "preventive maintenance"If taken literally, it's not legal to turn the lights off.14 CFR 91.213(d) says it must be logged and performed consistent with Part 43 if it is maintenance, but a pilot can do maintenance if it is classified as "preventive." CAP restricts this; see previous slide.CAWG does seem to classify pulling a circuit breaker as maintenance.But, there is disagreement; it depends which CAP flight instructor you ask.Unpublished "best practices" require it to be impossible to reenable the system unintentionally in flight. The source appears to be risk of restarting electrical fires when a breaker has been opened to service a previous fire.CAWG insists a breaker be held open with a zip tie or collarThere is elevated risk of CB damage, so it's probably notadvisibleto attempt this.Recommendation: have a mechanic perform this on CAP aircraft
Widely ignored in the private pilot community, but the regulation is clear.Any equipment permanently installed in the aircraft must work or be disabled and placarded.This includes CAP radios and DF.FAA requires 1/8" or larger lettering, but it can be written on a piece of masking tape (ref: AC 91-57)All CAP APs carry blue painter's tape and Sharpies
Sometimes disabling systems has a side effectExample: AP and electric trim are controlled by Avionics Bus 2.Turning off Bus 2 disables the aft avionics cooling fan, required by KOEL,and taking off is not permitted with Bus 2 turned off.A legally disabled system may result in hazardous flight under some conditions.Example: Both GPSsinop, but weather degrades to low instrument conditions. Only LPV approaches available within fuel range.Pilot's responsibility is to determine that flight safety is not compromised by the inoperative system.If there is any doubt, scrub the mission.
Application to AP DREX
AP DLSR sorties are almost exclusively hand-flown due to very frequent maneuvers beyond autopilot capabilities.Manual trim was working, with correct feel; electric trim judged unnecessary.Subsequent takeoff had an unrelated unexplained flapping noise, that the crew believed was a fuel cap. Precautionary landing to inspect revealed the oxygen tank strap was hanging out the door and both fuel caps were secure.MO was trained in round dial and overwhelmed by G1000, raising workload.Weather was becoming marginal over the photo target location (Sunol)PIC called for scrub after multiple issues and extra workload.Consequences: No aircraft damage, no injuries, no controllability issues beyond the trim setting. Overweight landing requiring inspection. Electric trim inspection found no anomalies. AP-T needs another sortie.
Inopequipment requires more than an assurance of safe operation for legal takeoffSystems understanding is criticalCAP requirements may be more stringent than FAAFlight school conventions are not always legalLaw of Primacy means a lot of pilots may bemistrainedAirworthiness rules and conventions are clear as mud, and published in several different places
AC 91-67, Minimum Equipment Requirements for General Aviation Operations Under FAR Part 9114 CFR 91.205, Powered Civil Aircraft with Standard Category US Airworthiness Certificates: Instrument and Equipment Requirements14 CFR 91.213, Inoperative Instruments and Equipment14 CFR 43 Appendix A, Major Alterations, Major Repairs and Preventive MaintenanceCAPR 66-1, Civil Air Patrol Aircraft Maintenance ManagementAirworthiness Directives,https://www.faa.gov/regulations_policies/airworthiness_directives/Type Certification Data Sheets (TCDSs), https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/Frameset?OpenPage