Equipment failures and emergency decisions

Control the aircraft, then identify what changed

An equipment emergency is a change in capability that may worsen while you investigate it. Start with reliable aircraft control, then perform the actual immediate actions/checklist, establish a usable route and communicate. The priorities overlap: a fire may demand an immediate checklist action, while a long troubleshooting sequence can wait until you can keep the aircraft stable. There is no universal switch sequence for every single-engine airplane.

Use the recognition lesson to distinguish a screen, sensor, pressure, gyro or power fault. Use the partial-panel lesson for remaining-reference control and approach preparation, and the lost-communication lesson for radio failure. This lesson focuses on urgency, automation, checklists and selecting a landing option.

A useful cockpit question is: what can the aircraft reliably do now, how long may that capability remain available, and what landing option can be reached within it? Do not substitute a successful previous flight or a universal battery-time estimate for that assessment. The course covers single-engine emergencies; it does not claim the multiengine one-engine-inoperative ACS tasks.

IFH Chapter 11: emergency operations · ACS VII.D: primary-instrument failure effects and control

Electrical failure is an endurance problem

A charging-system failure can leave equipment operating from a discharging battery for a time. A normal screen immediately after the alert does not establish that the system will last to destination. Interpret the actual ammeter/loadmeter, voltage, warning and bus indications under the aircraft documentation. Understand whether the fault affects charging only, a bus, a feeder, the battery, or the equipment itself.

Follow the aircraft checklist for any permitted restoration attempt, backup-source selection and load reduction. Determine which attitude, air data, navigation, communication, lighting, flap/gear and engine-related systems rely on the remaining power. Preserve required control information and landing capability; do not copy a generic list of “nonessential” loads into every aircraft. Backup-battery capacity, state of charge, temperature, health and connected loads govern endurance. The IFH contains illustrative installation examples; none supplies a guaranteed endurance for your aircraft.

Plan a timely suitable landing before capability declines. Report the fault, expected operational effects and assistance needed while communication remains available. A nearer suitable airport with better weather may be preferable to the original destination, even if the destination has maintenance. If smoke, heat or a fire indication accompanies the electrical problem, reassess it under the actual smoke/fire procedure rather than treating it as only a failed alternator.

IFH 11-5–11-7: charging-system failures and electrical use

Do not let automation turn a fault into loss of control

Primary controls change attitude: ailerons control roll, the elevator or stabilator controls pitch, and the rudder controls yaw. Secondary controls, such as flaps and trim, change performance or relieve control pressure. The connection may use cables, rods, hydraulic assistance or electrical commands, depending on the aircraft. Know your installation: loss of electrical power may disable electric trim or flaps while mechanical primary controls remain usable; other installations have different dependencies.

During the actual preflight and before-takeoff checks, verify the required control freedom and correct response, trim setting, flap operation and autopilot checks. In flight, abnormal resistance, missing response, a jam or asymmetric flap movement changes the available control and landing plan. Use the aircraft procedure and communicate the limitation; do not assume a generic trim or power change will solve every control failure. Consider the actual landing-distance and configuration consequences when selecting an airport.

The flight director and autopilot can command pitch/roll from attitude, heading, air data and navigation inputs. They also have servos, trim and mode logic. A sensor fault, wrong mode, unexpected command, trim problem or control interference can create an immediate aircraft-control hazard. Compare commanded/actual response and annunciations, and use the actual disconnect/override procedure when automation is unreliable.

Before IFR flight, know the normal manual-control feel, autopilot disconnects, trim procedures and required checks. The installation may specify a particular response to runaway trim, a stuck servo or an abnormal flight-control condition. Do not assume that one button removes every source of force or that pulling any guessed circuit breaker is harmless. Recover manual control using the actual emergency procedure and remaining reliable references.

When the system is otherwise serviceable but the selected mode/route is unsuitable, correct or disconnect it while maintaining control; do not follow an unwanted descent merely because a flight director displays it. After a confirmed failed attitude source, automation sharing that source is not an independent backup. Communicate inability to fly an assigned procedure and request manageable instructions.

IFH 11-7: instrument faults and autopilot/flight-director effects · ACS II.A.K2/R3: flight-control systems and automated-system use · PHAK 6-2–6-3 and 6-10–6-11: primary/secondary controls and trim · AFH 18-10–18-11: flight-control and flap failures; actual aircraft procedures govern

Smoke or fire changes the time available

Smoke, fire, burning odor or unusual heat can demand immediate action and a prompt landing. The Airplane Flying Handbook explains that an apparent extinguishment does not prove the source is removed or that structural damage is absent. Follow the actual aircraft smoke/fire checklist and emergency descent/landing procedure. A long return to the departure airport for maintenance can be inappropriate when the hazard may worsen rapidly.

Maintain control while addressing the source, protecting occupants and getting toward a suitable landing. The actual procedure governs electrical isolation, fuel/engine actions, extinguisher use, ventilation and whether any power may be restored. Ventilation can feed some fires, and restoring a circuit can recreate the fault. Do not cycle switches or reset a tripped breaker repeatedly to see whether a warning clears. Any permitted reset or restoration depends on the approved aircraft procedure and conditions.

If electrical isolation is required in IMC, identify which independent attitude/performance references remain available. Loss of radio/transponder may follow the required action; a concise distress call before isolation can help when time and the procedure permit. Do not delay a required fire action merely to finish a routine report. State the emergency and landing need when communication is possible. This is urgency reasoning, not an improvised fire checklist.

AFH 18-9–18-10: in-flight engine/electrical/cabin fire · AIM 6-1: immediate emergency assistance and authority

An engine loss requires a reachable landing plan

In a single-engine airplane, loss of engine power can remove climb capability and, depending on the installation, charging or vacuum power. Maintain control and the aircraft's appropriate engine-failure/glide performance while applying its checklist. Use the actual approved speed/configuration and restart conditions; this lesson gives no universal glide speed, range or restart sequence.

Choose a reachable suitable landing area using current position, altitude above terrain, wind, aircraft performance, obstacles, weather and available navigation. A map's nearest-airport list may rank distance without proving glide reach, runway availability or a safe route. Ask ATC for the assistance you need, including position, terrain/airport information or vectors when appropriate, but retain responsibility for aircraft control and feasibility.

A cloud base or an airway minimum is not a guarantee of an obstacle-free path after power loss. A conventional approach may be impossible if the aircraft cannot maintain its required profile. Use emergency judgment and the actual landing procedure, avoid stretching the glide by sacrificing control, and prioritize occupants over saving the aircraft. Engine-fire restart restrictions can differ from an ordinary engine failure; the aircraft checklist controls.

AFH 18-1–18-8: emergency landing considerations and control · 14 CFR 91.3: emergency authority

Choose a suitable option before margins disappear

Compare the remaining capability with landing options. Consider terrain/obstacles, weather, available approach guidance, runway and landing distance, power/fuel margin, navigation validity and workload. A slightly farther airport with a usable approach and better conditions may be safer than the geographically nearest field. Conversely, fire, rapidly declining power or control problems may leave no time for a lengthy diversion.

The table supplies no battery endurance guarantee. Verify actual airport status and capability, then request the appropriate route/approach. Be precise: “Charging system failed, operating on remaining battery, endurance uncertain; request nearest suitable landing with this navigation capability.” Under 91.187, report affected navigation/approach/communication equipment and the degree of impairment/assistance desired as soon as practical in controlled airspace under IFR.

Declare an emergency when needed; waiting for complete power loss makes assistance harder. Under 91.3(b), deviation is allowed to the extent required by an immediate-action emergency. When you deviate from a clearance under that authority, notify ATC as soon as possible and obtain amended instructions under applicable guidance. If communication itself fails, apply 91.185 and current AIM guidance unless the emergency requires other action.

14 CFR 91.187: malfunction report · 14 CFR 91.3: authority · AIM 6-1: assistance, urgency and clearance deviation

Prepare the response before the emergency

With an instructor, review the actual aircraft's electrical/vacuum dependencies, backup/reversion procedures, AFCS disconnects, engine-failure and smoke/fire checklists, and suitable landing planning. Practice safe simulated failures, prompt reference selection, control, checklists and capability-specific ATC requests. A written scenario cannot show that the pilot can fly the aircraft under these conditions.

After landing, complete postflight inspection and servicing under the checklist. Record observed indications, flight phase, alerts, settings, actions and results. Report the defect through the operator's process and identify the aircraft status. A recovered screen or restarted alternator does not by itself resolve an intermittent fault or approve return to service.

Debrief the decision timing: when did the evidence justify a diversion or emergency declaration, which tasks consumed attention, and what preserved a usable exit? Distinguish the good outcome from the quality of the decision. The next flight requires the applicable airworthiness and maintenance determinations, not simply a cleared message.

ACS VII.D: risk management and instructor-led application · 14 CFR 91.7: safe-flight condition · 14 CFR 91.407: return to service

FLIGHT SCENARIO

What would change your plan?