Open your cockpit window in smoke

[kuobin]

Hi gentleman:
If your cockpit window can be open below certain speed like B737, will you open your window in a smoke situation? what can we expect except strong noise and cold wind ?
:eek:

[john_tullamarine]

Subject to the OEM's procedures, generally no. Reason being that the external airflow usually is associated with a lower than cockpit pressure. ie all you are likely to do is suck smoke from the cabin into the cockpit and out the DV.

Better, usually, to leave the cockpit sealed and increase cabin alt (or depressurise completely) and use the outflow valve to do what it does best ...

[A37575]

Whether or not to open the cockpit window is comprehensively covered in the B737 QRH under the heading of smoke or fumes removal. Because it depends on the source of the smoke, best you read the QRH for the aircraft type to get the good gen.

[STBYRUD]

Our 733 QRH doesn't recommend opening the window for smoke removal in 'normal' configurations, after a number of items intended to increase ventilation using packs and pressurization valves it states
CAUTION: Do not open any flight deck window. Keep the flight deck door closed.Further down there is an entry for the case when "the packs are off and the smoke or fumes source is confirmed to be on the flight deck:"
CAUTION: Window should not be opened unless the source is confirmed to be on the flight deck.
Normal holding airspeed - Establish
First Officer's Sliding Window - Open
Return to SMOKE, FIRE OR FUMES checklist and do the remaining steps.

[A300-FO]

yes sir for my airbus type it can be open below 225kt

[A300-FO]

and the procedure sir to open it is
1-to open cockpit door
and it is recommended by airbus FCOM2 to open only 1 sliding window for a300-310
2-there is a point i dont understand in the procedure which is to select packs off and after opening the window select them to ON again
3-caution due to increased noise levels pay particular attention to visual warnings
hope that helps:)

[STBYRUD]

I guess the packs are turned off to avoid some sort of pressure surge ?! No idea. Just my guess.

[411A]

Depends on type, certainly.
Friend of mine died at BOS many years ago on a PanAmerican 707 freighter due to a dangerous goods fire aft, and they had to open the sliding cockpit window to try to see the instruments, the smoke was so thick.
This helped a bit, but not in time, sadly...the airplane crashed just short of the runway.
Investigation later proved improperly packed acid set the packing material (also not approved) on fire after the package tipped over....big fines for the shipping company and (I think) jail time for two execs of same.

Gotta know your type, folks....when it all goes pear-shaped.

I guess the packs are turned off to avoid some sort of pressure surge ?!
More than likely to get the window open in the first place.

[PEI_3721]

Open the cockpit window:- only when advised by the manufacturer’s SOP.
In some aircraft types, the air flow suction around the cockpit window draws smoke into the cockpit from the galley/cabin, possibly making the situation worse.
Expect noise and a lot of dust, and possibly distraction from flying paperwork etc.

[isaneng]

Having tried this for real, only a small airflow was induced until a few degrees of yaw was applied. Type specific or common to most frames with their aerodynamic similarities?

[glhcarl]

Better, usually, to leave the cockpit sealed and increase cabin alt (or depressurise completely) and use the outflow valve to do what it does best ...


How can you open the window without depressurizing. You have hundreds of pounds of pressure, holding the window shut.

[Bergerie1]

Many years ago I took part in an experiment on a VC10 to see whether opening a DV window would help remove smoke from the cockpit. We depressurised the aircraft, flew straight and level at (as I remember) around 5000ft and 230 kts. A smoke cannister was activated in the rear of the cockpit and each pilot in turn opened their DV windows (one at a time).

There were two effects:- (1) the stream of smoke came forward from the rear of the cockpit and then flowed across the instrument panel towards the open window reducing even further the visibility of the instruments on that side; (2) the noise was so great that conversation was almost impossible and we had to revert to hand signals.

I am sure that the aerodynamics of different aircraft would produce slightly dfferent results. But I would hesitate to open a cockpit window or hatch, if only for the reason that the noise renders normal cew coordination extremely difficult.

[SRTDub]

Quote:
Better, usually, to leave the cockpit sealed and increase cabin alt (or depressurise completely) and use the outflow valve to do what it does best ...

How can you open the window without depressurizing. You have hundreds of pounds of pressure, holding the window shut.


glhcarl you will find that john was merely referring to not opening the window atall and letting the outflow valve clear the smoke!

[albertofdz]

Opening the FO sliding window is essentialy the only move left when everything else has been done. This a desperate situation.


In order to understand why we would do such a thing, we must fully understand each and every step of the QRH.

The case upon which I would like to give my understanding, is the B737 (NG).

First of all we are directed to the "Smoke, Fire or Fumes" Non Normal Checklist, from know on to be refered as "NNC".

The first steps involve the ability of the crew to fight the hazard, so, if Smoke goggles and/or O2 masks are required, we will make use of these. (And establish comms via interphone),

Next, we are required to prepare the electrical system, in order to avoid any unwanted electrical power transfer form one transfer bus to another (737 has 2 transfer busses), due to the fact that from know on we are going to attempt to isolate a posible electrical problem that could be the culprate.

Next we disconnect the most frequent and therefore the most possible source of the fire. This includes all equipment located at the galleys (ovens, beverage makers, water heaters..... etc).

Following this, the Recirculation fans arwe disconnected. Why? 2 reasons: No1. We dont want to re circulate smoke.
No2. The recirculation fan/s (plastic and very toxic) may have set alight, and by disconnecting this, the fire may extinguish, and once again we a void recirculating hazardous smoke or fumes.

Next the APU BLEED air switch is set to OFF. The apu bleed duct travels form the back of the aircraft, right to the centre of the aircraft, where it joins the bleed duct on the left hand side of the X-bleed valve. This distance is long, and there may be a leak at any point. Extremely hot air from such a leak, will easily create a fire if in contact with glass fibre, cables, etc...

Up until now, all preliminary preparations have been done, and all highly possible sources have been dealt with. From now on, anytime smoke is the greatest threat, we will be directed to the "Smoke or Fumes Removal" checklist, if this is not the case, we continue with this NNC.

Next steps involves observation. Are the fumes/smoke decreasing? Can we confirm the source and disconnect this? If not, we continue with other possibilities, though these are less probable to be the cause.

Thes steps include switching OFF equipment cooling fans, and switching ON ALTN equipment cooling fans, the motive is the same as with the recirculation fans.

Passenger cabin lights are disconnected and reading lights switched on, this is basically to enhance visibility throughout the passenger cabin.

Final steps are time consuming, so we must be very carefull as to not delay the diversion to an airport whilst taking care of these steps. Take into account that a fire on board is extremely dangerous, so landing is prefered asap, even if items have not yet been completed. Many (me included) believe fire to be the greatest threat one will ever be challenged with during flight.

Following steps include disconnecting 1 pack (isolation valve closed) and waiting at least 2 minutes to see it smoke/fumes decrease. If this does not work, try with the other pack.

NNC offers no other possibility. If smoke/fumes continue (or if they stop, but it is considered neccesary)we can only try to put these outside of the aircraft. T

This takes us to the Smoke/fumes revomal NNC.

Steps during this NNC depend on the configuration of the Air/cond and Press system, more to the point, these depend on wether we may use the packs or not (obviuosly, if we disconnected a pack which was causing smoke/fumes, we will never switch it on).

If pack/s is/are available, we set them to HIGH, and LAND ALT is set to 10,000'. In normal conditions, the 737 cabin will be at 8000' when flying above Fl370. If we set 10.000' on the LAND ALT window, the cabin will raise from 8000 to 10.000', thus further opening the outlow valve and causing a strong stream of air towards the rear (outflow valve is located at the rear) which pulls smoke with it.

If smoke is still uncontrollable, we descend to 10000', and when below 14000', we are instructed to set the outflow valve to MAN, and fully open this. Just like before, this causes a strong stream of air towards the rear end, and smoke is dragged with it.

However if smoke is confirmed to be IN the flight deck, AND packs are OFF, there is only one alst way possible to evacuate smoke from the flight deck. This involves slowing to holding speed (normally between 210 and 220kts) and opening the FO sliding window (Flight deck door must be closed to avoid smoke coming in from the passenger cabin). This is very loud, but comms are still posible. The idea is as follows. A stream of relatively calm and stream line air flows outside of the window, this creates a region of lower pressure and by laws of physics air, and therefore smoke too, are drawn towards this region, putting the FO in quite an awkward position, but hopefully letting the CAPT read his instruments.



This is an awfully long explanation, but I beleive that in order to know why the sliding window would ever be opened, we must first fully undertand each and every step and scenario simulated by the QRH, from begging to end. Starting by isolating the most probable causes, and working towards an uncontrollable situation where drastic and desperate measures have to be taken.

Opening the window is not normally desired, but if we have no bleed air available, and the smoke is in the Flight deck, this is the most effective way to tackle teh situation.

Finally, please excuse my English! This is not my mother language.

[Centaurus]

Friend of mine died at BOS many years ago on a PanAmerican 707 freighter due to a dangerous goods fire aft, and they had to open the sliding cockpit window to try to see the instruments, the smoke was so thick

When the smoke first appeared in the cockpit it seeped through the circuit breaker panel leading the crew to believe they had an electrical fire on their hands. The F/E worked his way steadily through the specific checklist and this took some time as the checklist was designed as a trouble-shooting list.

If the crew had started an immediate descent instead of seeing if the trouble shooting would isolate which part of the electrical system was causing the smoke, the aircraft may have got on to the ground safely. It wasn't their fault but unfortunately they didn't know the smoke never was electrical in nature even though it seemed to originate from between the circuit breaker panels. As 411 stated it was a cargo hold fire of burning wood chips surrounding bottles of acid that had leaked. The local airflow through the aircraft meant the smoke came up from the cargo bay and through the CB's. The smoke which was hardly discernable at first, increased in intensity over the next few minutes and became so severe the crew could not even see the radio selections and were unable to change to required frequencies. Add to that the fact that toxic smoke can irritate eyes so badly they involuntarily shut and now things are really in the laps of the Gods.

The last item of the electrical fire trouble shooting checklist was battery switch off. I haven't flown a 707 but I gather that with landing flap down and speed brakes out, the yaw damper is inoperative with battery switch off and the aircraft becomes well nigh uncontrollable. This 707 crashed into a field while trying to reach the nearest airport.

Following the investigation into that accident, Boeing changed the checklist policy to cancel trouble shooting. This was because it was not always possible to differentiate between electrical fire and smoke and other fire and smoke sources. The long winded trouble shooting checklist caused lengthy delays when the aim should be to land as soon as possible.

When I flew for a European operator on the 737 on a short term contract in 1991, I was amazed the company still retained the original trouble shooting electrical smoke checklist - despite the revised Boeing procedure which explained why the old checklist was faulty.

When I questioned this policy I was informed in no uncertain terms that as some flights were out of sight of land, and thus landing at the nearest airport was a problem, it was decided to allow trouble shooting while en route to the nearest suitable airport.

So the long checklist was retained. This completely ignored the lesson of the fatal 707 accident which was that every second may count when smoke appears in the aircraft cockpit or cabin. And that it is vital to get on to the ground (in this case ditch on the sea) as quickly as possible because smoke could disable the crew before they could force land or ditch.

[BOAC]

How can you open the window without depressurizing. - I once flew with a Captain (who has been 'featured' on PPrune:)) who upon noticing that his drain tube had got stuck in the DV window and was making an unholy noise, decided without consultation, at 14000', to open the window to remove the tube

A) it opened
b) a fair bit of a/c paperwork went out of the window
c) I suggested he shut it again PDQ

[BOAC]

Oh yes! He put quite a lot of effort into it!

[Centaurus]

The 737 FCTM mentions a cockpit window can be opened in flight (unpressurised of course) and an area relatively free of wind blast is available.

Operating into Pacific atolls we occasionally encountered extremely heavy rain which blotted out forward vision. Alternate airports could be between 300 to 500 miles away and no certainty the weather would be good at the alternate. It was comforting to know that when all else fails and you had no choice but to land or ditch, the option was available to open a window and by tilting your head close to the open window you had enough forward vision to get the aircraft on the deck. The problem was always blinding rain obscuring the windshield and the window open option gave you a good chance of seeing more clearly.