Engine and APU Fire, and Engine Tailpipe Fire

From here the chapter is "the warning is real — now what". The hardware of engine and APU fire is settled in articles 03 and 04; this article develops the handling and decision — the reasoning behind the ECAM procedure, when to fire the second bottle, how to tell "fire out" from "detection destroyed", and the classic trap: an engine tailpipe fire looks like a fire but must never be handled as one.

1. The three "fire" scenarios

ENG FIRE is an external fire (outside the core) — starve and douse; TAILPIPE is an internal fire (inside the core) — cut fuel and ventilate. Their handling is nearly opposite.

2. ENG FIRE — confirmed by local warnings, without delay, discharge until the warning clears

The ECAM skeleton (from article 03): THR IDLE → ENG MASTER OFF → ENG FIRE pb PUSH → AGENT 1 (10 s windmilling) DISCH → ATC → if fire after 30 s, AGENT 2. The FCTM adds the decision philosophy:

"If the ENG 1(2) FIRE alert is confirmed by local warnings, the flight crew must apply the associated engine fire procedure without delay... The flight crew must complete all steps of the engine fire procedure and discharge agents as long as the ENG 1(2) FIRE alert is displayed and a local warning remains."

[!warning]- Discharge stops when the warning and the local warning clear — not "after two bottles" The "local warning" is the red light on the ENG/FIRE pushbutton, which follows the fire (article 03). It plus the ECAM alert are the dual confirmation that a real fire is burning; both clearing is what "fire out, stop" means. So the logic is discharge while watching the light — light still on, keep going (bottle 2 after bottle 1).

"the ENG FIRE alert and associated local warnings may disappear if the fire is successfully extinguished after the discharge of the fire extinguisher (1 or 1+2). In this case, the engine fire procedure can be stopped."

3. Light out ≠ fire out — the "false extinguish" of a burned detector

The single most dangerous mis-read in the chapter. A cleared light has two possible causes — genuinely out, or the fire has destroyed the detection system:

"If the flight crew delays the application... or if the fire is not successfully extinguished when the engine fire procedure is fully applied, the ENG FIRE alert and the associated local warnings may disappear due to damage to the engine fire detection system. However, a propagation of the fire may be indicated by a replacement of the ENG FIRE alert by an ENG FIRE DET FAULT alert. In this case, the flight crew should consider that the fire is not successfully extinguished and that the LAND ASAP is still applicable."

[!warning]- A cleared ENG FIRE light can be good news (out) or the worst news (you have gone blind) Distinguish them:

• Warning cleanly disappears after discharge → probably out.
• ENG FIRE replaced by ENG FIRE DET FAULT → the detection has been burned out (article 02: both loops failed = DET FAULT) → the fire is still burning, you have just lost your eyes → treat as not extinguished, LAND ASAP still applies. This welds the DET FAULT mechanism of article 02 to the fire decision: routinely a DET FAULT is a minor "detection degraded"; appearing mid fire-fight it is the death-notice that the fire has burned the detectors. Build the reflex: light out — ask, out, or blind?

The autopilot lightens the load:

"During flight, the use of autopilot in the case of an engine fire alert reduces the crew workload, and enables a safe handling of the thrust asymmetry..."

Shutting one engine yaws the aircraft; the autopilot trims it while the crew runs the procedure.

4. Engine tailpipe fire — looks like fire, must not be handled as one

First, what it is:

"An engine tailpipe fire can only occur at engine start or at engine shutdown. It is the result of an excess of fuel in the combustion chamber, in the turbine or in the exhaust nozzle, that ignites. A tailpipe fire is an internal fire in the engine, compared with an engine fire that occurs outside the engine core and gas path. No critical areas are affected in the engine in the case of a tailpipe fire. However, it can have an effect on the aircraft (e.g. damage the flaps)."

It raises no cockpit warning:

"In the case of a tailpipe fire, there is no cockpit alert. The only indication can be an increasing EGT due to the fire in the turbine. Therefore, most of the time, the ground crew, cabin crew, or ATC visually detect the tailpipe fire."

Why no warning (coupling into article 02): the detection loops are outside the core (nacelle/pylon); a tailpipe fire is inside the core (in the gas path), which the loops cannot sense — so it does not raise ENG FIRE. The handling:

"The flight crew must apply the QRH ENG TAILPIPE FIRE procedure, which requires the flight crew to: - Shut down the engine, in order to stop the fuel flow - Dry crank the engine, to remove the remaining fuel. The flight crew should not use the ENG FIRE pb. This cuts off the electrical supply of the FADEC, and stops the dry crank sequence performed by the FADEC. The flight crew should not use the fire extinguisher, as it does not extinguish an internal engine fire."

[!warning]- Both fire reflexes are wrong for a tailpipe fire

• Do not press the ENG FIRE pushbutton — it cuts FADEC power, and the dry-crank that ventilates the fire is run by the FADEC; pressing it severs your own means of extinguishing.
• Do not discharge Halon — it is sprayed outside the core and does nothing to a fire inside the gas path.
• The answer is "cut fuel + ventilate": shut down to stop fuel, dry-crank (motor without ignition) to blow the residual fuel out of the combustion chamber — starve plus ventilate, nothing to do with Halon. If the crank does not clear it, ground crew may use a ground extinguisher as a last resort (corrosive, requires maintenance). Hands off both buttons (FIRE pb / AGENT) — shut down, dry crank, ventilate.

5. APU FIRE — airborne manual, ground automatic

The APU hardware is settled in article 04; the procedure appears as the airborne/ground split:

"In Flight — EWD: APU FIRE / APU FIRE P/B PUSH / MASTER SW OFF / LAND ASAP. NOTE: In flight the crew must operate the APU fire-extinguishing system manually. On the Ground — EWD: APU FIRE / APU FIRE P/B PUSH / MASTER SW OFF. NOTE: On the ground the AFECU operates the APU fire-extinguishing system automatically if there is no manual operation from the cockpit."

[!warning]- Airborne carries LAND ASAP; the ground EWD does not A ground fire ends at the stand (possibly evacuation), no diversion; an airborne APU fire must plan a landing. Airborne the crew runs APU FIRE pb (shut down + cut fuel + close X-bleed + deactivate APU GEN) → MASTER OFF → AGENT; on the ground the crew largely watches the AFECU act in three seconds and confirms with APU SHUT OFF.

A ground engine fire additionally couples into evacuation (an emergency-procedure family, cross-chapter): complete the ENG FIRE procedure, and if the fire is uncontrolled, run EVACUATION. Ground fire = fire procedure + evacuation assessment in parallel; airborne fire = fire procedure + diversion (LAND ASAP).

Self-test

[!note]- Q1. When does ENG FIRE discharge stop? What is a "local warning"? When the alert and the local warning both clear. The local warning is the red light on the ENG/FIRE pushbutton, which follows the fire.

[!note]- Q2. Two bottles fired, light still on — meaning? Light out — is the fire always out? How to tell? Light on = not extinguished, keep going. Light out is ambiguous: clean disappearance (probably out) vs replaced by ENG FIRE DET FAULT (detection burned out, fire still on).

[!note]- Q3. ENG FIRE becomes ENG FIRE DET FAULT — meaning and action? The fire has destroyed the detection; treat as not extinguished, LAND ASAP still applies.

[!note]- Q4. Why does a tailpipe fire raise no cockpit warning? How do you learn of it? The loops are outside the core; a tailpipe fire is inside the gas path. You learn of it from rising EGT or an external report.

[!note]- Q5. Why never press ENG FIRE pb or discharge agent for a tailpipe fire? What is correct? The FIRE pb cuts FADEC power and stops the FADEC dry-crank; Halon cannot reach an internal fire. Correct: shut down + dry crank to ventilate residual fuel.

Key takeaways

References

• FCTM PR-AEP-ENG (ENGINE FIRE) — local-warning confirmation, without delay, discharge to warning clearance, light-out ambiguity (extinguished vs detection damage), FIRE → DET FAULT = fire not out, autopilot for asymmetry.
• FCTM PR-AEP-ENG / QRH ENG TAILPIPE FIRE — internal fire at start/shutdown, no cockpit alert / EGT, shut down + dry crank, prohibitions on FIRE pb (cuts FADEC/stops dry crank) and extinguisher.
• AMM 26-21-00 — ENG FIRE ECAM procedure (developed in article 03).
• AMM 26-13-00 — APU FIRE airborne manual vs ground AFECU automatic.

Independent study material, not an Airbus publication and not endorsed by the manufacturer. Always defer to the current operator FCOM, FCTM, and QRH for operational use.