Embraer E-Jet Fire Protection and Oxygen
On the Embraer E190-E2, fire protection comprises two detection loops and two cross-connected bottles for the engines, detection and a bottle for the APU, smoke detection and two bottles for the cargo compartments, and lavatory smoke detection; the oxygen system comprises a crew cylinder, passenger chemical generators and portable equipment.
The Embraer E-Jets watch their engines and APU with fire detectors and their cargo compartments and lavatories with smoke detectors, and the E2 also has smoke detection in its electronics bays. Fixed extinguisher bottles serve the engines, the APU and the cargo compartments, and the lavatory waste bin has its own extinguisher. For breathing, the flight crew have gaseous oxygen from a cylinder, the passengers have chemical oxygen generators, and portable bottles and protective breathing equipment (PBE) complete the system.
Figures are those of the E190-E2 unless another model is named. The engines and the APU themselves are described in E-Jet engines and APU. The principles are in fire and overheat detection, engine fire protection, cargo and lavatory fire protection, crew oxygen systems and passenger and portable oxygen, and the A320's arrangement in A320 fire and smoke protection.
Engine fire detection and extinguishing
Each engine has two fire detection loops, A and B, and each loop has 2 × 4 pneumatic fire detectors in the engine core. The loops are split between two modular avionics units: engine 1 loop A and engine 2 loop B are connected to MAU 1, and engine 1 loop B and engine 2 loop A to MAU 3, so that each engine has one loop on each MAU and no single MAU carries both loops of the same engine.
An engine fire gives a master warning, an aural warning, the ENG FIRE message and a FIRE indication on the engine's ITT indicator on EICAS, and it lights the engine's fire handle. Actuating the engine fire handle closes the engine's fuel, hydraulic and bleed air shutoff valves (see E-Jet fuel system and E-Jet hydraulic system).
The two engine extinguisher bottles, A and B, are on the right side of the rear wing-to-fuselage fairing, and they are cross-connected.
Warning: if the fire handle light goes out but the ENG FIRE message is still displayed, the fire condition still exists, whatever the handle light shows.
APU fire protection
The APU bottle is forward of the APU compartment. Two buttons act on the APU in an emergency:
- APU EMER STOP closes the APU fuel shutoff valve, shuts the APU down at once and arms the bottle; a white stripe appears in the button.
- APU FIRE EXTINGUISHER discharges the bottle, shuts the APU down through the APU FADEC and closes the APU fuel shutoff valve.
On the ground, if APU EMER STOP has not been pressed, the APU shuts down automatically 10 seconds after a fire is detected. If EMER STOP has not been pressed after a minute of APU fire warning, the APU FIRE EXTINGUISHER button lights red and the bottle is armed; pressing that button discharges it.
Exam tip: EMER STOP stops the APU and arms the bottle but does not discharge it. The bottle is discharged with the APU FIRE EXTINGUISHER button.
Cargo fire protection
The EASA type-certificate data sheet classes both underfloor cargo compartments of the first-generation E190 (ERJ 190-100, except the ECJ) as Class C, 12.5 m³ forward and 10.1 m³ aft, and the E190-E2's compartments are Class C too.
Cargo smoke detection uses fan-type photoelectric smoke detectors in the compartment ceilings, and two detectors must sense smoke before the master warning is generated. Transport Canada's operational evaluation report gives the number of detectors by model:
| Model | Forward compartment | Aft compartment |
|---|---|---|
| E170, E175 | 3 | 2 |
| E190 (E1) | 4 | 3 |
| E195-E2 | 4 | 4 |
When smoke is detected, the FWD or AFT button lights, the CRG FWD (AFT) SMOKE warning appears and the high-rate bottle is armed. For the forward compartment, the ventilation fan is also disabled and the cargo shutoff valve closes.
The cargo extinguishing system has two bottles in the centre electronics bay, a high-rate bottle followed by a low-rate bottle that lasts 75 minutes. Both can be discharged into either compartment.
| Situation | Discharge |
|---|---|
| In flight, with the master warning | One push fires the high-rate bottle; the low-rate bottle follows automatically after 1 min, or earlier if pushed |
| On the ground, with the master warning | One push fires the high-rate bottle; the low-rate bottle needs its own push |
| Without a master warning | Two pushes within 2 min fire the high-rate bottle; the selection resets automatically after 2 min |
Exam tip: in flight, after CRG FWD SMOKE, a single push on the FWD button is enough: the high-rate bottle fires at once and the low-rate bottle follows by itself after 1 minute. On the ground there is no automatic low-rate discharge.
Lavatory and electronics bay smoke
The lavatory smoke detector, on the ceiling, senses smoke through ionised air between electrodes and gives the LAV SMOKE master warning; the deploy tool silences its horn. The waste bin has a separate extinguisher, with no cockpit indication.
The E2 has smoke detection in its electronics bays. Its FWD, CTR and AFT EBAY SMOKE checklists replace the RECIRC SMOKE checklist, and Transport Canada's report confirms the E2's e-bay smoke detection system and the FWD, CTR and AFT EBAY SMOKE EICAS messages.
Fire tests
A 2-second press of the TEST button on the fire extinguisher panel tests 10 lights and 5 messages, plus EBAY SMOKE on the E2, and deactivates the forward cargo fan. On the ground, holding TEST for more than 10 seconds shuts the APU down.
Exam tip: a 2-second press of TEST checks the lights and messages; on the ground, holding TEST for more than 10 seconds also shuts the APU down.
Crew oxygen
The flight crew breathe from a rechargeable 77 ft³ cylinder, at a nominal 1,850 psi at 21 °C, in the forward cargo compartment; Transport Canada lists the standard 77 ft³ cylinder as an E2 difference. The bottle discharges overboard at 2,700 psi at 21 °C (2,450 psi at 71 °C). The overboard discharge indicator is on the right-hand fuselage and is green when all is well; the exterior inspection item reads "Discharge indicator green disc".
| Crew oxygen indication | Meaning |
|---|---|
| Green, 1,150 psi | Dispatch with three crew members in the cockpit |
| Cyan, 842 psi | Dispatch with two crew members |
| Amber | No dispatch |
CREW OXY LO PRESS comes with the master caution and relates to 12 minutes of oxygen for two pilots. OBSERVER OXY LO PRESS is only an advisory: the pressure is below the limit for three crew members.
On the regulator of the crew oxygen masks, NORM supplies diluted oxygen, 100 %, the default position, supplies 100 % oxygen, and EMER adds positive pressure. The mask is designed to be donned within 5 seconds and automatically starts the oxygen flow, the speaker and the mask microphone; with OXY AUTO selected, taking it out of its box selects the mask microphone and activates the speakers. To test a mask, with 100 % selected, the crew check that the flow indicator shows a yellow star which then disappears.
Passenger oxygen
The passengers' oxygen comes from chemical generators in the passenger service units (PSUs). A generator starts when its mask is pulled, and it gets very hot. The masks are of the diluter type and give no protection from smoke, and the mask doors are electrically actuated.
In AUTO the masks deploy automatically above 14,000 to 14,750 ft, and the crew can also deploy them manually with OVRD. Automatic deployment is controlled by SPDA 1, and its altitude switch is in the forward electronics bay, near the CPCS. When the masks deploy, the NO SMKG and FSTN BELTS signs come on automatically and an ON caption is shown.
Exam tip: automatic mask deployment is controlled by SPDA 1, not by the CPCS, even though the altitude switch sits near the CPCS in the forward electronics bay.
The generators supply oxygen for 12 minutes on the E190-E2 and 22 minutes on the E195-E2. On the E2 the lavatory oxygen is not chemically generated but stored in a bottle, and the EASA data sheet for the ERJ 190-300 and -400 records a finding on how the crew determine the oxygen quantity in the lavatory and cabin oxygen bottles.
Portable oxygen and PBE
The 310 l portable oxygen bottles have two flow settings: 2 l/min, the low (left) position, for walking in the cabin, and 4 l/min for first aid. Their minimum dispatch pressure is 1,200 psi (30 minutes). The portable bottles of the first-generation E190 hold 11 ft³ at 1,800 psi.
The protective breathing equipment (PBE) supplies 15 minutes of oxygen, protects against smoke and toxic gases and can be used up to 25,000 ft.
Exam tip: 12 minutes is the E190-E2 passenger generator, 22 minutes the E195-E2's and 15 minutes the PBE. The passenger masks drop above 14,000 to 14,750 ft and give no smoke protection; the PBE does.
Messages and indications
| Message or indication, E190-E2 | Meaning |
|---|---|
| ENG FIRE, with master warning and aural warning | Engine fire; FIRE also shown on the ITT indicator |
| APU FIRE EXTINGUISHER button lit red | APU fire warning for 1 min without EMER STOP; bottle armed |
| CRG FWD (AFT) SMOKE, master warning | Smoke sensed by two detectors; high-rate bottle armed |
| LAV SMOKE, master warning | Smoke in the lavatory |
| FWD, CTR or AFT EBAY SMOKE | Smoke in an electronics bay |
| CREW OXY LO PRESS, caution | Relates to 12 min of oxygen for two pilots |
| OBSERVER OXY LO PRESS, advisory | Crew oxygen below the limit for three crew members |
Frequently asked questions
What does the engine fire handle do on the E190-E2?
Actuating the engine fire handle closes the engine's fuel, hydraulic and bleed air shutoff valves. The two engine bottles, A and B, are on the right side of the rear wing-to-fuselage fairing and are cross-connected. A fire is shown by a master warning, an aural warning and a FIRE indication on the ITT indicator. If the handle light goes out but the ENG FIRE message remains, the fire condition still exists.
How does APU fire protection work on the E190-E2?
APU EMER STOP closes the APU fuel shutoff valve, stops the APU at once and arms its bottle. The bottle is discharged with the APU FIRE EXTINGUISHER button, which also shuts the APU down through its FADEC. On the ground the APU shuts down automatically 10 seconds after a fire is detected if EMER STOP has not been pressed. If EMER STOP has still not been pressed after 1 minute of fire warning, the extinguisher button lights red with the bottle armed.
How are the E190-E2 cargo fire bottles discharged?
Two bottles in the centre electronics bay serve both compartments: a high-rate bottle and a low-rate bottle lasting 75 minutes. With a smoke master warning in flight, one push fires the high-rate bottle and the low-rate bottle follows automatically after 1 minute, or earlier if pushed. On the ground the low-rate bottle needs a push. Without a master warning, the high-rate bottle needs two pushes within 2 minutes.
How long does E190-E2 passenger oxygen last?
The chemical generators supply oxygen for 12 minutes on the E190-E2 and 22 minutes on the E195-E2. A generator starts when its mask is pulled, and the masks deploy automatically above 14,000 to 14,750 ft, or when the crew select OVRD. The masks are of the diluter type and give no protection from smoke; the PBE does, supplying 15 minutes of oxygen up to 25,000 ft.
What is the minimum crew oxygen pressure for dispatch on the E190-E2?
The crew oxygen indication is green at 1,150 psi, which allows dispatch with three crew members in the cockpit, and cyan at 842 psi, which covers two; amber means no dispatch. The rechargeable 77 cubic foot cylinder has a nominal pressure of 1,850 psi at 21 degrees C. CREW OXY LO PRESS, a caution, relates to 12 minutes of oxygen for two pilots.
Test yourself on Embraer E-Jet Fire Protection and Oxygen
The v1prep banks cover this topic in the E-Jet type-rating bank, with a worked explanation for every answer. EASA ATPL, PPL, IR and CPL, the FAA written tests and type ratings for the A320, 737, A220, 787, ATR 72 and E-Jet.
Start practising →Sources and further reading
- EASA Type-Certificate Data Sheet EASA.IM.A.071, Embraer ERJ 190 (ERJ 190-100, -200, -300 and -400)
- Transport Canada Civil Aviation, Operational Evaluation Report, Embraer E-Jets (E1 and E2), Revision 1, 2023
- 14 CFR 25.1203, Fire detector system
- 14 CFR 25.1195, Fire extinguishing systems
- 14 CFR 25.857, Cargo compartment classification
- EASA Easy Access Rules for Large Aeroplanes (CS-25), CS 25.857, CS 25.1195 to CS 25.1203 and CS 25.1439 to CS 25.1453
- FAA Aviation Maintenance Technician Handbook, Airframe (FAA-H-8083-31B), Chapters 16 and 17, oxygen systems and fire protection
Library articles are written for study and exam preparation. They do not replace your aircraft's approved documentation, your operator's procedures or the regulations themselves.