Emergency Checklist for Cabin Smoke and Fire Incidents in Boeing 737

Introduction

Smoke or fire in the cabin of a Boeing 737 is among the most critical in-flight emergencies. The confined space, high passenger density, and presence of combustible materials demand immediate, precise actions from the cabin crew. This article provides a comprehensive, step‑by‑step emergency checklist specifically tailored for the Boeing 737, integrating regulatory requirements, aircraft‑specific features, and best practices from airline standard operating procedures (SOPs). Proper execution of these steps can mean the difference between a controlled incident and a catastrophic outcome. Cabin crew members must internalize this checklist through recurrent simulator training and constant vigilance.

Understanding Cabin Smoke and Fire in the Boeing 737

Common Sources of Smoke and Fire

Fire in the cabin can originate from multiple sources. Understanding these helps crew members assess the situation faster:

Galley equipment: Coffee makers, ovens, and hot cups can overheat or short‑circuit.
Lavatory systems: Discarded cigarettes in waste bins or faulty flush motors may ignite paper towels.
Lithium‑ion batteries in passenger electronic devices – a growing risk due to thermal runaway.
Overhead bins or seat electronics (in‑seat power, IFE screens) can experience electrical faults.
Clothing or luggage catching fire due to accidental contact with heating elements.

Aircraft‑Specific Considerations for the Boeing 737

The Boeing 737 family (‑NG and MAX) features a relatively narrow cabin with overhead storage bins that can restrict access to the ceiling area. Many models have a forward and aft galley and two lavatories. The location of fire extinguishers (typically one in the forward cabin and one in the aft) and the placement of the Protective Breathing Equipment (PBE) must be memorized. The cabin also features a manual fire detection system for the lavatory waste bins (heat‑activated extinguishing agent) and automatic smoke detectors in some configurations. Crew must be familiar with the location of the emergency equipment panel and the operation of the passenger oxygen system – which in the 737 is chemically generated and cannot be turned off once deployed.

Immediate Actions (First 30 Seconds)

1. Alert the Crew and Cockpit

Announce loudly and clearly: “Fire, fire, fire! Cabin crew to stations!” Use the interphone (handset or push‑to‑talk) to inform the cockpit. State your name, location (e.g., aft galley), and nature of the incident (smoke visible, flames, suspected source).
If smoke is present, the flight crew will likely declare an emergency and may initiate an emergency descent. Immediate communication saves seconds.

2. Don Protective Breathing Equipment (PBE)

Each cabin crew member must don a PBE before approaching the fire. The Boeing 737‑specific PBEs (e.g., smoke hood or full‑face mask) provide a 15‑minute supply of oxygen and protect against toxic gases. Practice opening the pouch and fitting the hood correctly during every recurrent training.
If PBE is not available, improvise with a wet cloth over the nose and mouth – but never delay fire‑fighting for that. Prioritize donning the PBE if it is within reach.

3. Activate Passenger Oxygen Masks (If Needed)

If smoke or fire threatens the breathable air, the flight crew will deploy passenger oxygen masks via the cockpit switch. If they do not, and the cabin becomes full of smoke, inform the cockpit immediately. The masks are automatically deployed when the cabin altitude exceeds 14,000 feet, but during a fire at lower altitude, manual deployment may be necessary.
Do not deploy masks unnecessarily – once activated, they cannot be stowed again and will deplete the chemical oxygen generator.

4. Assess the Fire: Source, Size, and Type

Look – see if flames are visible or only smoke. Smell for electrical odor (burnt wire) versus paper/trash.
Identify the class of fire:
- Class A: Ordinary combustibles (paper, wood, textiles) – use water or Halon/CO₂ (but water may damage electronics).
- Class B: Flammable liquids (alcohol, fuel) – use Halon or CO₂.
- Class C: Electrical equipment – use non‑conductive agents (Halon, CO₂).
- Class D: Combustible metals (rare in cabin; typically in cargo hold).
Size: A “small” fire can be contained with a single extinguisher. A “large” fire (bigger than a small wastebin) requires additional units and immediate evacuation consideration.

Fire Suppression Actions

5. Select and Use the Appropriate Fire Extinguisher

On the Boeing 737, the standard extinguishers are Halon 1211 (typically 2.5 lb or 5 lb) or CO₂ (15 lb). Halon is preferred for electrical fires and confined spaces because it leaves no residue and is safe for occupants.
P‑A‑S‑S technique:
- Pull the pin.
- Aim at the base of the flames (not the smoke).
- Squeeze the handle.
- Sweep from side to side.
If using a CO₂ extinguisher, be aware of the risk of asphyxiation in a small cabin space – ensure ventilation after discharge.
Use the fire axe (if needed) to break open panels or access hidden fires. This is a last resort; typically, the extinguisher alone suffices for small fires.

6. Isolate the Fire and Cut Off Air Supply

Close all nearby compartment doors – lavatory doors, overhead bin doors, galley stowage doors.
If the fire is inside a lavatory waste bin, close the bin flap and turn off the nearby electrical systems (if safe). The waste bin is equipped with a thermal‑activated extinguisher (usually a Halon cartridge). Do not open the bin if smoke is escaping – let the extinguisher work.
Turn off galley power by using the galley power switch or circuit breaker (located on the galley panel or the overhead PSU).
If the fire involves an electronic device (e.g., a laptop), do not use water – use a Halon extinguisher or cover the device with a fire‑resistant container (e.g., a “lithium‑ion battery fire bag” if available).

7. Ventilate the Cabin – Only If Safe

If smoke is thick but the fire is extinguished, open the vent flaps on the overhead PSU (if possible) to clear smoke. On the Boeing 737, the overhead vent is a small circular knob that can be opened to the stop.
However, never ventilate while the fire is still active – fresh air can “feed” the flames. Only ventilate after the fire is confirmed out and all smoldering material is cooled.
The flight crew may also pressurize the cabin or initiate an emergency descent to increase fresh air circulation – coordinate with them.

Passenger Management

8. Give Clear, Calm Instructions

Use the public address (PA) system: “Ladies and gentlemen, please remain seated with your seat belt fastened. Place your head between your knees if smoke is heavy. Breathe through a cloth if available. Do not leave your seat until instructed.”
Repeat key instructions: “Stay low – crawl if necessary.” Smoke rises, so breathing near the floor reduces inhalation of toxic gases.
Advise passengers to cover their nose and mouth with any available fabric (jacket, blanket).

9. Assist Vulnerable Passengers

Designate a second crew member to locate and assist elderly, disabled, or non‑English‑speaking passengers. Use hand signals and show the emergency paths.
If a passenger is in immediate danger from the fire (e.g., seated next to the source), relocate them to the nearest unaffected seat row, ensuring they are buckled in.
Do not obstruct aisles with luggage – instruct passengers to leave all carry‑on bags behind.

10. Prepare for Evacuation – When to Call It

If the fire cannot be extinguished within one minute or if it grows despite efforts, the cabin crew must prepare for an emergency evacuation.
Silent review: Quickly assess which doors are usable. Smoke outside the aircraft? Fire visible from the window? Order: “Cabin crew, prepare for emergency evacuation – disarm doors only when instructed.”
Signal the flight crew via interphone or cabin call light. Use the codes: “Emergency evacuation” for immediate, “Prepared for evacuation” for imminent.
Activate emergency lighting – switch on the floor path lighting and overhead emergency lights. On the Boeing 737, the emergency lighting switch is usually on the forward attendant panel and can be set to ARM or ON. If not automatic, manually turn it on before the aircraft comes to a stop.

Evacuation Execution

11. Brace Commands and Door Operation

Shout: “Brace! Brace! Head down, stay down!” The cabin crew themselves must brace near a strong object (e.g., galley seat, bulkhead).
After the aircraft comes to a complete stop, the flight crew will give the order to evacuate (or if they are incapacitated, the senior cabin crew can order it).
Assess outside conditions: Look through the door window. If fire or debris is present, do not open that door. Redirect passengers to another exit.
Open the door (or if the slide is required, disarm the girt bar and throw the slide). The Boeing 737 slide is self‑inflating; ensure the lanyard is attached to the aircraft.
Once the slide is deployed, guard the door and command: “Jump! Jump! Do not sit – jump!”

12. Direct Passengers to Safe Exits

Use strong, repetitive verbal commands. Point to the nearest usable exit. Shout: “This way! Leave everything!”
If smoke obscures vision, use the floor proximity lighting. The Boeing 737’s floor path lights are brightly colored and follow the aisle; instruct passengers to crawl and follow the lights.
Help passengers who are pinned or injured, but do not block the flow. The priority is to clear the cabin as fast as possible.

Post‑Incident Procedures (After Fire Is Contained or Evacuation Complete)

13. Assess the Aircraft Condition

If the fire is extinguished and evacuation is not required, coordinate with the flight crew to decide whether to divert to the nearest suitable airport or continue flight (only if completely safe and no smoke remaining).
Check for any smoldering remnants. Use a thermal imaging camera (if available) or carefully feel surfaces with the back of the hand.
Monitor the cabin for any recurrence of smoke or fire. Assign two crew members to remain on watch with a charged extinguisher.

14. Medical Assessment and First Aid

Treat passengers suffering from smoke inhalation – provide oxygen via a portable oxygen bottle (if available). The Boeing 737 carries one or two portable oxygen bottles (POB) in the cabin crew stations.
Check for burns, respiratory distress, or shock. Use the first aid kit. If a passenger is unresponsive, begin basic life support (CPR) and use the automated external defibrillator (AED) if trained.
Prepare a list of injured passengers for ground medical services.

15. Documentation and Communication with Ground Services

After landing (whether diverted or continued), the cabin crew must provide a detailed incident report to the flight crew and ground authorities. Include:
- Time the fire was discovered.
- Location (e.g., aft lavatory, row 18 overhead bin).
- Actions taken (extinguishers used, doors closed, evacuation order given).
- Any injuries or unusual behavior.
- Serial numbers of used extinguishers and PBEs.
Coordinate with ramp services and airport emergency responders – point out the exact location of the fire source for inspection.

16. Post‑Flight Inspection and Debrief

The cabin crew must not disturb the fire scene. Airlines have safety and maintenance teams that will investigate.
Debrief with the entire crew: discuss what went well and what could be improved. This is vital for crew resource management (CRM) and future training.
Write a factual, concise report for the company’s safety department – avoid opinions, stick to observations.

Crew Training and Coordination (CRM)

17. Importance of Recurrent Hands‑On Drills

The Boeing 737’s cabin layout changes slightly between variants (‑700, ‑800, ‑900ER, MAX). Crew must practice locating extinguishers, PBEs, and lavatory waste bin extinguishers.
Simulate a hidden fire scenario: crew should practice using a fire axe to access panels above the ceiling panels (near the galley or overhead bins).
Train with the actual PBE – including fitting it while standing, then crawling to the fire source.

18. Communication with the Cockpit

Use the dedicated fire‑call – a long‑press of the cabin interphone button often sets off a priority chime in the flight deck. If no response, use the PA handset.
Provide clear updates: “Fire is out / Fire is still burning / We are evacuating.” In a pressurized cabin, the flight crew may be occupied with checklists – be concise.
If the cockpit is suspected to be compromised (smoke entering through the door), use the flight deck door observation window to pass written notes.

19. Use of Aircraft Systems for Smoke Removal

The flight crew can operate the smoke clearance mode of the air conditioning packs and set the cabin to emergency pressurization. Cabin crew should never touch engine or bleed air controls.
If smoke is heavy, the flight crew may request cabin crew to close all overhead vent flaps to prevent smoke from recirculating.

External References for Further Study

Conclusion

Effective response to cabin smoke and fire on the Boeing 737 is a product of preparation, swift decision‑making, and unwavering coordination among crew members. Every second counts – from the initial detection to the moment the fire is suppressed or the cabin is evacuated. By following this expanded checklist, cabin crew can reduce panic, prevent escalation, and protect the lives of passengers and fellow crew. Regular simulator drills, thorough knowledge of aircraft equipment, and a clear chain of communication form the backbone of a successful outcome. Stay calm, act quickly, and follow the checklist.

Emergency Checklist for Cabin Smoke and Fire Incidents in Boeing 737

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