7.3 Operating with Inoperative Equipment Without an MEL (14 CFR 91.213(d))

7.3 Operating with Inoperative Equipment Without an MEL (14 CFR 91.213(d))

[!NOTE] General Aviation Relief Standard: The vast majority of single-engine and light twin-engine general aviation aircraft operate without an FAA-approved Minimum Equipment List. For these aircraft, 14 CFR § 91.213(d) provides the primary legal mechanism authorizing flight with inoperative equipment. An Inspection Authorization (IA) holder must master the rigorous four-step screening process required by § 91.213(d) to determine whether an inoperative instrument may be safely deferred, deactivated, or removed, or whether it grounds the aircraft.

Under general operating rules, taking off in an aircraft with inoperative equipment is strictly prohibited unless an explicit regulatory exception applies. While large, turbine-powered multi-engine aircraft typically operate under the formal MEL framework of 14 CFR § 91.213(a), the Federal Aviation Administration recognized that developing and maintaining an operator-specific MEL is administratively burdensome for small general aviation aircraft. To resolve this, the FAA codified 14 CFR § 91.213(d), establishing a self-contained, four-step evaluation sequence that pilots and maintenance professionals must execute prior to flight.

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Scope and Applicability of 14 CFR § 91.213(d)

Title 14 CFR § 91.213(d) is not universally available to all civil aircraft. The regulation specifically restricts its relief to the following categories of aircraft operating under Part 91 without an approved Minimum Equipment List:

• Rotorcraft, non-turbine-powered airplanes, gliders, lighter-than-air aircraft, powered parachutes, and weight-shift-control aircraft for which a Master Minimum Equipment List has not been developed (§ 91.213(d)(1)(i)); or
• Small rotorcraft, non-turbine-powered small airplanes, gliders, or lighter-than-air aircraft for which an MMEL has been developed (§ 91.213(d)(1)(ii)).

The two-part structure matters. Existence of an MMEL for the type does not by itself close the § 91.213(d) door: a small non-turbine airplane may still use paragraph (d) even though an MMEL exists for its type. A larger non-turbine airplane with an MMEL cannot.

Ineligible Aircraft Categories

Turbine-powered airplanes (turboprops and turbojets), regardless of operation under Part 91, are statutorily excluded from utilizing 14 CFR § 91.213(d). A turbine-powered airplane cannot take off with inoperative equipment under Part 91 unless it possesses an FAA-approved MEL and Letter of Authorization under § 91.213(a) or obtains a Special Flight Permit under 14 CFR § 21.197.

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The Comprehensive Four-Step Regulatory Check

Before an inoperative instrument or piece of equipment can be legally deferred under 14 CFR § 91.213(d), it must successfully pass through a sequential, four-step regulatory gauntlet. If the inoperative item is required under any single step, the aircraft is legally unairworthy and cannot be flown.

                  [Inoperative Equipment Discovered]
                                  │
                                  ▼
      [Step 1: Required by Type Certification Basis (VFR-Day)?] ────► YES ──► GROUNDED
                                  │ NO
                                  ▼
      [Step 2: Required by Aircraft Equipment List / KOEL?]   ────► YES ──► GROUNDED
                                  │ NO
                                  ▼
      [Step 3: Required by 14 CFR § 91.205 or Part 91 Rules?] ────► YES ──► GROUNDED
                                  │ NO
                                  ▼
      [Step 4: Required by an Airworthiness Directive (AD)?]  ────► YES ──► GROUNDED
                                  │ NO
                                  ▼
      [Item May Be Legally Deferred: Deactivate or Remove, Placard & PIC Check]

Step 1: VFR-Day Type Certification Airworthiness Regulations

The technician or pilot must determine whether the inoperative equipment is part of the VFR-day type certification instruments and equipment prescribed in the airworthiness regulations under which the aircraft was type certificated.

• Certification Basis Reference: The aircraft's certification basis is specified in the Type Certificate Data Sheet (TCDS). For older vintage aircraft, this is Civil Air Regulations Part 3 (CAR 3.655); for modern aircraft, it is 14 CFR Part 23 (§ 23.1303, § 23.2615).
• Typical Required Items: Airspeed indicator, sensitive altimeter, magnetic direction indicator (compass), oil pressure indicator, oil temperature indicator, tachometer, cylinder head temperature indicator (for cowl-flapped engines), and manifold pressure gauge (for altitude engines). If any of these baseline type certification instruments is inoperative, the aircraft fails Step 1 and cannot fly.

Step 2: Aircraft Equipment List or Kinds of Operations Equipment List (KOEL)

The second hurdle requires examining the manufacturer's official equipment documentation published in the FAA-approved Pilot's Operating Handbook (POH) or Aircraft Flight Manual (AFM):

• Equipment List: Found in Section 6 of the POH, the comprehensive equipment list designates items with an "R" (Required), "S" (Standard), or "O" (Optional). Any item designated as "R" is mandatory for all flight operations.
• Kinds of Operations Equipment List (KOEL): Found in Section 2 (Limitations) of modern Part 23 aircraft, the KOEL specifies equipment requirements categorized across four operational flight regimes: VFR Day, VFR Night, IFR Day, and IFR Night. If an inoperative item (such as a pitot heat system or second alternator) is marked as required for "IFR Night," and the intended flight is under IFR at night, the aircraft fails Step 2 and cannot be dispatched.

Step 3: Specific Operating Rules of 14 CFR Part 91

The third hurdle requires cross-referencing all applicable operating regulations under Part 91 for the specific flight operation being conducted:

• 14 CFR § 91.205 Operational Equipment:
  • VFR Day (§ 91.205(b)): ATOMATOFLAMES (Airspeed, Tachometer, Oil pressure, Manifold pressure, Altimeter, Temperature gauge, Oil temperature, Fuel gauge for each tank, Landing gear position indicator, Anti-collision lights [for aircraft certificated after March 11, 1996], Magnetic compass, ELT, Safety belts/harnesses).
  • VFR Night (§ 91.205(c)): FLAPS — approved position lights (c)(1); an approved aviation red or white anticollision light system (c)(2); if operated for hire, one electric landing light (c)(3); an adequate source of electrical energy (c)(4); and one spare set of fuses or three spare fuses of each kind required (c)(5).
  • IFR Operations (§ 91.205(d)): GRABCARD (Generator/alternator, Radios/navigation gear suitable for route, Sensitive altimeter, Ball/slip-skid, Clock with sweep second hand or digital display, Attitude indicator, Rate-of-turn indicator, Directional gyro).
• Additional Part 91 Regulations: Operating rules outside § 91.205 must also be satisfied, including § 91.207 (Emergency Locator Transmitter), § 91.215 (ATC transponder and altitude reporting equipment), and § 91.225 (ADS-B Out equipment within rule airspace).

Step 4: Airworthiness Directives (14 CFR Part 39)

The final hurdle requires verifying whether an Airworthiness Directive mandates that the inoperative system or component be operational. If an AD mandates that an auxiliary fuel pump, avionics annunciator, or stall warning horn be functional, that item can never be deferred under § 91.213(d).

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Four-Step Screening Decision Matrix Table

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Resolving Discrepancies: Deactivation vs. Removal Protocols

If the inoperative equipment passes all four steps without being required, 14 CFR § 91.213(d)(3) mandates that the equipment be handled by one of two methods. Get the subparagraph letters the right way round — the regulation lists removal first:

• § 91.213(d)(3)(i) — the instruments and equipment are removed from the aircraft, the cockpit control placarded, and the maintenance recorded in accordance with § 43.9.
• § 91.213(d)(3)(ii) — the instruments and equipment are deactivated and placarded "Inoperative." If the deactivation involves maintenance, it must be accomplished and recorded in accordance with Part 43.

Method A: Deactivation and Placarding — § 91.213(d)(3)(ii)

Under § 91.213(d)(3)(ii), the equipment may remain in the aircraft provided it is properly deactivated and placarded:

• Physical Deactivation: The unit must be rendered completely inoperable to prevent inadvertent activation or electrical hazard during flight. For electrical avionics and appliances, this requires pulling the associated circuit breaker and installing an approved mechanical lockout collar (or safety tie-wrap) around the breaker stem. If the unit is mechanically or pneumatically driven, plumbing must be disconnected and securely capped.
• Mandatory Placarding: A durable, clearly legible placard bearing the word "INOPERATIVE" must be affixed directly on or adjacent to the control switch, circuit breaker, and cockpit display in full view of the pilot.
• Maintenance Authorization: While simple deactivation not involving complex disassembly can be performed by the pilot under preventive maintenance guidance, complex wiring disconnects or hydraulic isolation must be performed by a certificated A&P mechanic.

Method B: Physical Removal and Weight/Balance Revision — § 91.213(d)(3)(i)

Under § 91.213(d)(3)(i), the equipment may be physically removed from the airframe. Note that the rule itself calls for the cockpit control to be placarded and for the maintenance to be recorded under § 43.9:

• Maintenance Signoff: Physical removal of a component from an aircraft panel or structure constitutes an airframe maintenance action that must be performed by authorized maintenance personnel under 14 CFR § 43.3 and signed off under 14 CFR § 43.9.
• Weight and Balance Recalculation: Removing an instrument or avionics box shifts the aircraft empty weight and center of gravity. Under 14 CFR § 43.5, the technician must compute the new Empty Weight and Empty Weight Center of Gravity (EWCG) and formally update the aircraft weight and balance records.
• Equipment List Amendment: The comprehensive equipment list in Section 6 of the POH must be updated by redlining or striking out the removed item to reflect current airframe configuration.

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Deactivation vs. Removal Comparison Table

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The Pilot-in-Command Safety Gate (14 CFR § 91.213(d)(4))

Even when an item passes all four screening hurdles, is properly collared, and bears an "INOPERATIVE" placard, one final legal barrier remains before flight:

• The PIC Determination: Title 14 CFR § 91.213(d)(4) dictates that a determination must be made by an appropriately certificated pilot or mechanic that the inoperative instrument or equipment does not constitute a hazard to the aircraft for that specific flight.
• Operational Context: For example, an inoperative cabin heater valve in freezing conditions might lead to windshield fogging or pilot incapacitation from hypothermia, creating an unacceptable hazard even though a cabin heater is not listed in § 91.205. If the PIC determines that the condition compromises safe flight, the aircraft cannot be flown.

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High-Yield Exam Traps & Regulatory Distinctions

• Turbine Aircraft Are Excluded from 91.213(d): A perennial IA exam question asks if a twin-turboprop aircraft without an MEL can deactivate an inoperative autopilot under § 91.213(d). The answer is NO. Turbine-powered aircraft cannot use § 91.213(d); they must have an FAA-approved MEL or a Special Flight Permit.
• Removal Requires Weight and Balance Recalculation: Removing an inoperative unit under § 91.213(d)(3)(i) requires the cockpit control to be placarded and the maintenance recorded under § 43.9, and it changes the empty weight and EWCG, so the weight and balance records and equipment list must be updated for the aircraft to remain operable within its § 91.9 limitations.
• Do Not Transpose the Subparagraphs: § 91.213(d)(3)(i) is removal; § 91.213(d)(3)(ii) is deactivation and placarding. A distractor that swaps them is the most common way this question is written.
• Circuit Breaker Pulling Alone Is Insufficient: Simply pulling a circuit breaker does not fulfill § 91.213(d). The breaker must be collared to prevent accidental resetting, and the unit must be prominently placarded "INOPERATIVE."
• Landing Lights When Flying for Hire: Under 14 CFR § 91.205(c)(3), one electric landing light is required for night flight if the aircraft is operated for hire. If a flight instructor charges for dual instruction at night, the aircraft is operating for hire and an inoperative landing light cannot be deferred under § 91.213(d).