Is it true that on most modern passenger jets that cockpit smoke can be cleared by opening a window? at low?

Question

Smoke For Thought

In 1986 the FAA published an internal Advisory Circular that stated, (quote) "Incidents of fire and smoke that cannot be extinguished continue to occur. New and modified smoke and fire procedures should be formulated, considering that the fire or smoke exposure may be continuous" (unquote).

altitude hopefully. How long to descend from 30,000 ft to 9,000 ft?
Up-to-date, nothing has been done. In May 1927, the smoke
evacuation procedure on Charles Lindberg’s "Spirit of St Louis" was to open the window. Today on an Airbus A340 it is still the same.

The accident statistics themselves indicate that it is now the time to open serious discussions about the effectiveness of existing procedures. Only in the USA, over the last 5 years, the FAA have had approximately 4000 smoke reports. (Yes, you read that correctly, 4000!). These figures include all types of operations, commercial and non-commercial, but exclude the military. Thirty percent (30%) resulted in unscheduled and emergency landings.

We are led to believe, by the aircraft manufacturers, that existing smoke evacuation procedures work. However, those pilots who were involved in in-flight fire emergencies with dense smoke in the cockpit, and who could have given us valuable feedback on the effectiveness of such procedures, are all dead.

The common factor in almost all fire emergencies resulting in total hull-loss with fatalities, is that the time frame between the first indication that something was wrong (i.e. smell, circuit breaker tripping), and the fatal crash, is anywhere from several to a maximum of 18 minutes. Present emergency procedures depend on isolating the possible cause of the fire, and evaluating the result of such action. This takes time, and, armed with the above knowledge, time is precisely what we do not have.

And, the fire risks are increasing. The present no-smoking regulations on board aircraft are welcomed by many. However, these smoking restrictions have resulted in concealed smoking by passengers, and in some cases even crewmembers, increasing the risk of an in-flight fire. (How many lavatory smoke alarms did you have lately?).

As I said earlier, it is time to start discussions on this topic. Hear are some thoughts...

I believe that the first line of the checklist, "land as soon as possible", is the most important consideration, with the emphasis on "as soon as possible", and in my opinion should override other limitations such as overweight landing. I would rather be alive to defend my decision making than otherwise. What this means if our nearest landing runway (suitable or non-suitable) is more than 30 minutes away is that a controlled crash landing or ditching is perhaps the only option. Obviously this is a decision that few people would like to make.

In a case of dense smoke in the cockpit I wonder how, in the first place, you can read the different items on the checklist, and secondly how you can find the relevant controls on the overhead panel. I don’t even want to think about the guy who has to fly the aircraft and most probably without an autopilot, due to checklist actions, and without any visual reference whatsoever. In such a situation I believe that the first action is to get rid of the smoke which brings you to the last part of the checklist – "If cockpit window opening required".

Answer 1

You illustrate why we have checklists.



The cockpit ( Boeing calls it a control cabin, for PC purposes) is pressurized to a very slightly higher pressure than the rest of the cabin. So the cockpit window(s) are only opened if the source of the smoke is confirmed to be in the cockpit because we don't want to suck any more of the bad-nasty air into the front.



The B737 checklist has about 14 items on it, and can probably be accomplished in as few as 30-40 seconds. Of course, it says land at the nearest suitable airport.

Answer 2

You asked about "modern" aircraft then quoted an AC from 1986...



"opening a window" is an option...if we decide to do it. However we do not use checklists like you probably have ever used. We use something known as a QRH which is a several hundred page emergency checklist book where you use a flowchart to diagnose a problem. IF you were to encounter this, the first item on the checklist would probably read:



Oxygen Masks: DON--100% O2



After that, you would diagnose the problem and correct it. Only after that is done and the fire is extinguished would there be an entry that tries to clear the smoke from the cockpit. If we were able to extinguish the fire, and if the smoke persisted, and if the airplane we are flying has windows that are able to open in flight (very doubtful...I don't know if you've ever tried to oppose 9 pounds per square inch over 200 or so square inches) then maybe windows open would be an option.



A Cessna 172 is not a modern airliner. Its checklist procedures are not relevant to commercial aviation. I once had an instructor who insisted that I wear long pants when I fly in case the insulation on the wires melted and dripped on my legs. That is not an emergency procedure, it illustrates how out of touch people who fly those things are with the world of airline flying. In our world, a fire is a major MAJOR emergency. In that emergency we follow a QRH procedure, diagnose a problem, and fix it. If there is residual smoke AFTER THE FIRE HAS BEEN EXTINGUISHED, we have procedures for clearing smoke out of the cabin/cockpit. What I want to illustrate is that the smoke clearing is not an emergency procedure, its an after-emergency procedure.



Oh and as to "finding the relevant controls", we pretty much can grab any switch, knob, button, or dial simply from muscle memory. We don't really need to see them.



And also..I have had exactly zero LAV SMOKE alarms. Ever. In my entire career. If we did have one, it would primarily be the job of the FA to extinguish it.



Ditching because of a smoker in the lav would be idiotic. If we caught fire over northern Canada and were unable to extinguish the fire, maybe ditching would be an option, but since thousands of aircraft make that trek over the North Atlantic tracks and we haven't had that happen, I'd say the chances of a cigarette burning an airplane up in flight are pretty remote.

Answer 3

Wow what a doosy.



Anyway, in a small airplane, opening the window may make the flames worse as this provides fresh oxygen for the fire to feed on. Probably the same for larger airplanes. However, if the fire is extinguished then there is no problem.



Larger pressurized airplanes cannot open windows until they descend below 10,000 feet. I do not know how long this takes but the emergency oxygen masks that pop down last about 10 minutes, which is supposed to be long enough for the pilot to get the plane down to 10,000 feet so I'll say 5 minutes should be a reasonable amount of time.



Not having flown in a larger jet I do not know what the procedures are but I do believe that airplanes should land as soon as practicable. The term land as soon as possible indicates that you should land at the nearest flat spot (off airport). Practicable means a suitable airport (meaning not an airport with a 1500 foot runway for a 747).



Generally since an airplane is usually en route to the nearest airport at the first sign of smoke, and since it usually happens at high altitude, the logical thing to do is to troubleshoot the cause of the problem and hopefully prevent it from getting worse.

Answer 4

The control cabin of Boeing commercial transport planes are not pressurized any more than the rest of the aircraft. There is no reason to do so. In the event of smoke in the aircraft, one measure the crew can take (in the 767) is to select "override" on the equipment cooling select on the P5 panel (overhead). This shuts off the cooling fans (stop moving air around, feeding oxygen to the fire) and opens a dump valve in the belly of the aircraft. The differential pressure of the aircraft will force air out of the valve, taking smoke out with it, by design. This is only intended as a short term solution, as there is no active equipment cooling for the mass of computers and controllers located in the main equipment center.



Opening the window in flight is likely to cause a variety of other problems. As the windows that could be opened are more on the front of the aircraft, this is more likely to cause more wind blowing into the aircraft, than moving smoke out. This could also "fan the fire" causing the problem to get worse.

Answer 5

The inboard armrest shown interior the photograph is often up while the team climbs into the cockpit, so getting into is easier than it seems. yet particular, there are some 'gymnastics' in contact in mountaineering over the pedestal between the seats. the respond on your 2d question with reference to the keypad and green demonstrate screen contraptions is that those are the Flight administration device (FMS) administration contraptions and that they are area of the navigation device for the plane. There are generally a minimum of two of those onboard for redundancy and in many cases a third as properly. They coach direction of flight, way-factors, time to holiday spot, direction information, and frequencies for airports on the direction. a number of companies make those, alongside with properly-known, Honeywell, and Collins.