Wheel Well Fire Actions....
Thread Starter
Join Date: Oct 2002
Location: In Frozen Chunks (Cloud Cuckoo Land)
Age: 17
Posts: 1,521
Likes: 0
Received 0 Likes
on
0 Posts
Wheel Well Fire Actions....
Hypothetically:
If you are at cruise altitude - say 39000' - and have been there for a while - say 60 mins after takeoff....and you get a wheel well fire warning -
what would your thoughts/actions be?
For info assume landing gear limit is 270kts/.82M (B767)
There are several reasons I ask this question:
1 - high speed aerodynamics is not my strong point - hence the interest in extending the gear at high altitude (as per the Non Normal Checklist) - so if anyone wants to tackle a good explanation of IAS / mach crossover feel free - the effects of compressibility and resulting effects on gear doors etc
2 - the likelihood of a genuine wheel well fire warning so long after takeoff....
Cheers
If you are at cruise altitude - say 39000' - and have been there for a while - say 60 mins after takeoff....and you get a wheel well fire warning -
what would your thoughts/actions be?
For info assume landing gear limit is 270kts/.82M (B767)
There are several reasons I ask this question:
1 - high speed aerodynamics is not my strong point - hence the interest in extending the gear at high altitude (as per the Non Normal Checklist) - so if anyone wants to tackle a good explanation of IAS / mach crossover feel free - the effects of compressibility and resulting effects on gear doors etc
2 - the likelihood of a genuine wheel well fire warning so long after takeoff....
Cheers
Join Date: Oct 2005
Location: USA
Posts: 3,218
Likes: 0
Received 0 Likes
on
0 Posts
Wheel well fire at FL390? What's out there to burn? Not a lot burns in that atmosphere...very high probability of a false indication.
Gear speeds are generally indicated airspeeds, and that's what you go by at altitude. Verify the speed, put out the gear where appropriate, in accordance with the checklist, if warranted.
Gear speeds are generally indicated airspeeds, and that's what you go by at altitude. Verify the speed, put out the gear where appropriate, in accordance with the checklist, if warranted.
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes
on
0 Posts
Cancel the warning and continue reading the newspaper....unless you might have other indications.
Very unlikely at cruise altitude (long time) if it has not been indicated before.
Don't know about Airboos, however...
Very unlikely at cruise altitude (long time) if it has not been indicated before.
Don't know about Airboos, however...
Thread Starter
Join Date: Oct 2002
Location: In Frozen Chunks (Cloud Cuckoo Land)
Age: 17
Posts: 1,521
Likes: 0
Received 0 Likes
on
0 Posts
I agree with the false indication being the most likely reason as per 411A - but - tend to agree with directanywhere with regard to actioning the checklist.
My only comment would be - how long would it take for other indications to make themselves apparent - would you wait to find out?
The Wheel well detector is a single loop - and shouldnt be tripped for hot brakes. There isnt a great deal else in the gear bay that would trip it is there? Unless some hydraulic system has caught fire..... not sure what would though (HMG out of control?) .
Some of our other guidance material (training manual) suggests slowing to 250kts - presumably for an adequate margin.
If at or above optimum - putting the gear out will also presumably put you at your thrust limit aswell - so force a descent - not sure how fast this would happen - depending on gross weight etc.
My only comment would be - how long would it take for other indications to make themselves apparent - would you wait to find out?
The Wheel well detector is a single loop - and shouldnt be tripped for hot brakes. There isnt a great deal else in the gear bay that would trip it is there? Unless some hydraulic system has caught fire..... not sure what would though (HMG out of control?) .
Some of our other guidance material (training manual) suggests slowing to 250kts - presumably for an adequate margin.
If at or above optimum - putting the gear out will also presumably put you at your thrust limit aswell - so force a descent - not sure how fast this would happen - depending on gross weight etc.
Join Date: Jul 2005
Location: n/a
Posts: 221
Likes: 0
Received 0 Likes
on
0 Posts
I would have thought that it is impossible to assume a false warning until proven otherwise - and one should act in a conservative manner.
I believe it would be prudent to treat any indication of a wheel well fire as an actual occurrence, requiring prompt actioning of the appropriate checklist. Without suppression capability - time would be of the essence to conduct a timely diversion and landing.
Thought provoking exercise: as mentioned previously unable to maintain altitude due to gear extension, diversion to an enroute airport, fuel flow with gear down and ability to actually divert to an airfield with the gear still down or the need to retract the gear at a later stage, how to handle the landing regarding possible braking difficulties/reduced stopping performance, or asymmetric braking on a field length limited airport, use of reverse thrust, where and how to park the aircraft - into wind, on the runway or other, cabin preparation required and how to manage the aircraft and occupants after landing? At an airport with RFF and smoke around the wheels (no reports of flames or communication/language problems) do you bang the doors and exit? Or at an airfield with no support or communication?
Life, universe and everything? 42
I believe it would be prudent to treat any indication of a wheel well fire as an actual occurrence, requiring prompt actioning of the appropriate checklist. Without suppression capability - time would be of the essence to conduct a timely diversion and landing.
Thought provoking exercise: as mentioned previously unable to maintain altitude due to gear extension, diversion to an enroute airport, fuel flow with gear down and ability to actually divert to an airfield with the gear still down or the need to retract the gear at a later stage, how to handle the landing regarding possible braking difficulties/reduced stopping performance, or asymmetric braking on a field length limited airport, use of reverse thrust, where and how to park the aircraft - into wind, on the runway or other, cabin preparation required and how to manage the aircraft and occupants after landing? At an airport with RFF and smoke around the wheels (no reports of flames or communication/language problems) do you bang the doors and exit? Or at an airfield with no support or communication?
Life, universe and everything? 42
Join Date: Dec 2001
Location: Somewhere over the rainbow
Posts: 234
Likes: 0
Received 0 Likes
on
0 Posts
B767
Checklist Introdution.
"There are some situations where the crew must always land at the nearest Available Airport. These situations include, but are not limted to, conditions where:
- The non-normal checklist has the words "Plan to land at the nearest Available Airport"
The Wheel Well fire checklist includes this line.
Also in the Checklist Introduction (my Bolding)
"It must be stressed that for persistent smoke or a fire that cannot be positively confirmed to be completely extinguished, the earliest possible descent, landing and evacuation must be done"
I am fully aware that, as PIC, you can vary checklists if required, however Boeing have gone to pains to stress an immediate landing, and I think I'd have serious questions for any crew that chose to ignore this one.
Checklist Introdution.
"There are some situations where the crew must always land at the nearest Available Airport. These situations include, but are not limted to, conditions where:
- The non-normal checklist has the words "Plan to land at the nearest Available Airport"
The Wheel Well fire checklist includes this line.
Also in the Checklist Introduction (my Bolding)
"It must be stressed that for persistent smoke or a fire that cannot be positively confirmed to be completely extinguished, the earliest possible descent, landing and evacuation must be done"
I am fully aware that, as PIC, you can vary checklists if required, however Boeing have gone to pains to stress an immediate landing, and I think I'd have serious questions for any crew that chose to ignore this one.
Join Date: Apr 2000
Location: NL
Posts: 27
Likes: 0
Received 0 Likes
on
0 Posts
Its not so hypothetical, I experienced it on a CRJ in FL310 after about 25 minutes of flight.
Bing, bing, bing.
Pulserate 200.
Whats up?
Wheel well fire? Here at this level? After 25 minutes? The computer must have gone wild!!
Actions taken: CPT makes PA announcement. I took control. descended rapidly and then (in my recall) level off at F250, slow down to max gear and do the procedure.
Message went out.
In my opinion, this is the only safest course of action. Reading newspaper...HA. Where are u coming from.....
Bing, bing, bing.
Pulserate 200.
Whats up?
Wheel well fire? Here at this level? After 25 minutes? The computer must have gone wild!!
Actions taken: CPT makes PA announcement. I took control. descended rapidly and then (in my recall) level off at F250, slow down to max gear and do the procedure.
Message went out.
In my opinion, this is the only safest course of action. Reading newspaper...HA. Where are u coming from.....
Warning Toxic!
Disgusted of Tunbridge
Disgusted of Tunbridge
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
Likes: 0
Received 0 Likes
on
0 Posts
I can recall a 727 long ago had a wheel well fire. Heat from the brakes can take a significant time to spread to the tyre and heat it up to cause trouble. I would take any fire warning as genuine and land nearest suitable.
Join Date: Jul 2002
Location: A Marriott somewhere
Posts: 213
Likes: 0
Received 0 Likes
on
0 Posts
Brake temps
I would check brake temps, then go take a look with my belly mounted camera to see if there were any indications of fire. Then I would do whatever I decide as PIC is the most prudent thing to do at that point and follow the recommended checklist procedure.
Join Date: Jun 2005
Location: AEP
Age: 80
Posts: 1,420
Likes: 0
Received 0 Likes
on
0 Posts
Whel well fire - 747
In the 747, unlike 707, 727 and DC8, we have brake temperature gages.
As per company procedures/policies, we only takeoff with temperature in GREEN.
If brakes temperature continues to rise after gear retraction, extend the gear.
xxx
If fire warning BELL comes ON, for WHEEL WELL FIRE, crosscheck brake temperatures.
If brake temperature are in the RED zone, extend the gear.
The "gear doors open" with that procedure no longer required by Boeing.
If the gear brakes temperature is normal, it is captain's decision.
Likely to be a false warning.
xxx
Suggestion to those of you still doing "touch and goes" with airliners...
Leave your gear DOWN for an entire circuit every 3 landings for gear cooling.
And mention to your boss that simulators are good enough. No fuel used.
xxx
Happy contrails
As per company procedures/policies, we only takeoff with temperature in GREEN.
If brakes temperature continues to rise after gear retraction, extend the gear.
xxx
If fire warning BELL comes ON, for WHEEL WELL FIRE, crosscheck brake temperatures.
If brake temperature are in the RED zone, extend the gear.
The "gear doors open" with that procedure no longer required by Boeing.
If the gear brakes temperature is normal, it is captain's decision.
Likely to be a false warning.
xxx
Suggestion to those of you still doing "touch and goes" with airliners...
Leave your gear DOWN for an entire circuit every 3 landings for gear cooling.
And mention to your boss that simulators are good enough. No fuel used.
xxx
Happy contrails
Join Date: May 2008
Location: Scotland
Age: 80
Posts: 451
Likes: 0
Received 0 Likes
on
0 Posts
On 747 classics it is possible to get a wheel well fire warning from a leaking pneumatic duct in the left wheelwell - it is pressurised in flight from the engines although it is usually referred to as the APU duct.
I have seen this in the case of a duct joint which was sealed with high temp sealant which blew out - it should have had seal rings but the Mexican FAA approved maintenance organisation was out of stock at the time of a check! If both wing isolation valves were closed the warning should stop - you would be a bit short of breath though!
I have seen this in the case of a duct joint which was sealed with high temp sealant which blew out - it should have had seal rings but the Mexican FAA approved maintenance organisation was out of stock at the time of a check! If both wing isolation valves were closed the warning should stop - you would be a bit short of breath though!
Join Date: Jul 1999
Location: 58-33N. 00-18W. Peterborough UK
Posts: 3,040
Likes: 0
Received 0 Likes
on
0 Posts
The world's most infamous wheel well fire?
Report on the Diierrenaesch Accident. A preliminary report, just
published, of the investigations into the Swissair Caravelle crash at
Diierrenaesch on September 4 last year (1963) concludes, as predicted
during the initial investigation, that overheating of the brakes prior
to take-off was the primary cause. The aircraft had caught fire in the
air and crashed five minutes after taking off from Zurich. The fire
started when the tyres of the two rear wheels of the four-wheel port
undercarriage bogie burst, causing damage to hydraulic and fuel
pipes, with the fluid and fuel subsequently catching fire on contact
with the hot brakes. The fire was also fed by the rubber tyres and the
magnesium rims of the wheels. The report, written by M Carl
Hoegger, director of the enquiries, notes that the aircraft was taxied
to and fro along the runway to clear the ground fog and states
that such "tunnelling manoeuvres" are not regarded as an official
operating procedure for Caravelles. This technique had, it appears,
once been described in Swissair's Caravelle operating manual, but
was dropped from the 1962 manual onwards. The effects of a
tunnelling manoeuvre on the temperature of the brakes and wheels
had never been analysed.
http://www.flightglobal.com/FlightPD...20-%202341.PDF
Report on the Diierrenaesch Accident. A preliminary report, just
published, of the investigations into the Swissair Caravelle crash at
Diierrenaesch on September 4 last year (1963) concludes, as predicted
during the initial investigation, that overheating of the brakes prior
to take-off was the primary cause. The aircraft had caught fire in the
air and crashed five minutes after taking off from Zurich. The fire
started when the tyres of the two rear wheels of the four-wheel port
undercarriage bogie burst, causing damage to hydraulic and fuel
pipes, with the fluid and fuel subsequently catching fire on contact
with the hot brakes. The fire was also fed by the rubber tyres and the
magnesium rims of the wheels. The report, written by M Carl
Hoegger, director of the enquiries, notes that the aircraft was taxied
to and fro along the runway to clear the ground fog and states
that such "tunnelling manoeuvres" are not regarded as an official
operating procedure for Caravelles. This technique had, it appears,
once been described in Swissair's Caravelle operating manual, but
was dropped from the 1962 manual onwards. The effects of a
tunnelling manoeuvre on the temperature of the brakes and wheels
had never been analysed.
http://www.flightglobal.com/FlightPD...20-%202341.PDF
Join Date: May 2007
Location: Castlegar
Posts: 255
Likes: 0
Received 0 Likes
on
0 Posts
Wheel Well Fire Safety
Wheel Well FIRE INDICATOR? It's still NOT required by Part 25. The Douglas Products still do NOT have Wheel Well FIRE Detection (even after NationAir DC8fatal Hull Loss.
After ValueJet, industry went back to the 1947 regulations (the narrow-body's Fwd Cargo and Aft Cargo Compartments must have Detection/Protection). But the ValueJet CHANGES never forced WHEEL WELL Detection for DPD's DC9's, MD8's and DC8s.
What would have been the result, if the following GRND mishap, had instead happened inflight:
After ValueJet, industry went back to the 1947 regulations (the narrow-body's Fwd Cargo and Aft Cargo Compartments must have Detection/Protection). But the ValueJet CHANGES never forced WHEEL WELL Detection for DPD's DC9's, MD8's and DC8s.
What would have been the result, if the following GRND mishap, had instead happened inflight:
NWA / 3Jan98 DC9-51 N-776NC, ground mishap at DTW. Wheel Well fire, electrical wire (three phase) powering Aux Hydraulic Pump overheated after one phase failed. See FAA Incident Rpt 980103002669C, FAA web page.
Here's that PropAir case:PropAir / 18Jun98 Sweringin Metro II diverted to Mirabel YMX crashed landed approach to Rwy 06-24, left side on fire, incl the engine -- observed by firefighters. Left wing departed with the engine in flames; off the rwy, swampy ditch, overturned. 11 sob killed. CVR recovered; MP mentioned that a/c suffered inflt breakup (wing separation) prior to landing. CBC rpts of 26Sep stated TSB/c said pilot did not know the source of smoke was a fire in the Left MLG Wheel Well [retracted]; hot break, fire, NO INDICATION. Design-annunciation of a/c should show WARNING of fire in wheel well. CBC Rpt 26Oct, final AAR not expected until '99.
Here's that monster fire, pilots crash landed:USAF / 27Sep74 Lockheed C-5A 68-0227 hull loss: Wheel Well fire, in-flight, uncontained, at night, crashed-landed at grass airport (rwy lights in sight) at Clinton OK. [ Later mod'd LG Wells for fire detection and suppression. Date & ship # from Bill Harms, details merely from memory.]
Here's a B737 case, not wheel/tire really:Pan Am / 2Apr86 B737 N164AF taxi-out at London LHR, at #1 spot prior to takeoff, following aircraft spotted smoke coming from the B737's Wheel Well area. An electric Hydraulic Pump had shorted, burnt through casing, hydraulic fluid-spray ignited. [Flt Int'l, 24Jan87, pg 39.]
Here's an example a what could occur on any DPD product (eg, an MD8):Nationair / 11Jul91 Canadian registered DC-8-61 C-GMXQ ... crashed after an inflight fire; impacted 1.75 miles short of runway 34C at Jeddah. Prior to flight, mechanic determined that an inboard tire on Left MLG had low-pressure. To avoid a delay aircraft dispatched without servicing tire. \\ F/O's takeoff, at 50 Kts (15 seconds and 500' of roll) noted sounds of flat tire, followed by sound of second “flat” 2 seconds later. Flames visible in the left main gear until gear was retracted after T/O. \\ Taxi on under-inflated tires caused over-deflection, overheating and structural weakening of the tire. Friction created enough heat to start a self-sustaining fire; two wheels severely damaged, and piece of broken wheel rim struck the airframe (embedded in left flap). When gear retracted after T/O, burning rubber brought near hydraulic and electrical system components. Wheel well fire involved tires, hydraulic fluid, magnesium alloy and jet fuel (fire burned through center fuel tank). Fire spread from Wheel Well to Cargo Compartment, cabin floor was breached, control systems disabled. Cabin pressurization lost, hydraulic pressure lost. \\ Five minutes after brake release for T/O, F/A entered cockpit and reported, "smoke in the back, real bad." While at 2000' on downwind leg, SSW of field, CVR recorded F/O's comment, "I've got no ailerons!" Crew told ATC there was fire onboard, declared an emergency, and said they were returning to base. On final 11 miles out (suspected point that LG was extended) numerous pax bodies fell from the aircraft. \\ Airframe structural integrity lost, control lost prior to impact. Impacted 1.75 miles short of Rwy 34C. \\ Lessons: dangerous under-inflation of tire not discernible visually. After T/O, gear should not have been retracted. Sob = 14 + 247; all killed. [Extract of Saudi report in AWST Oct25'93 pg 49; better rpt excerts from ICAO's AAD; and "NTSB Reporter" Nov'93. DG's"AD" pg 214+ has some errors.]
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes
on
0 Posts
The aircraft had caught fire in the
air and crashed five minutes after taking off from Zurich
air and crashed five minutes after taking off from Zurich
New(er) pilots simply have to look at realities of the situation to make a reasonable decision.
In the heavy jets that I fly, we sure as heck aren't getting to 390 anytime soon after takeoff...far too heavy.
It would be at least six hours into the flight, and that would be optimistic.
Any sort of tire/brake problems resulting from an overheat during taxi/takeoff would have manifested itself far sooner than the time to reach FL390.
Bleed air leak from a duct that passes through the unpressurized wheel well area?
We have duct overheat sensors for that on the type that I fly so...these would indicate a problem, independantly of the wheel well overheat sensors.
Don't specifically know about the many types that pilots might fly here, but on the type I fly (L1011)....yes, barring any other confirming indication...cancel the bell and resume reading the newspaper.
Gotta know your specific type folks...general scenarios simply will not result in a one-size-fits-all approach.
Join Date: Feb 2007
Location: Tralfamadore
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
What a nightmare.
I've never read a worse gear fire story than that NationAir story. If it isn't a "landmark accident," it should be. Thanks for posting it, it'll be in the back of my mind on every preflight.
Join Date: Mar 2000
Location: Arizona USA
Posts: 8,571
Likes: 0
Received 0 Likes
on
0 Posts
I've never read a worse gear fire story than that NationAir story.
However, you might note that this scenario did not occur at FL390, but instead, right after takeoff.
It was also in an older type with poor (or no) overheat loop protection.
A completely different scenario from what was originally posted.
I repeat, gotta know your specific type folks, you absolutely cannot generalize.
In the type that I fly, wheel well overheat situations (and that is precisely what these loops do, they indicate an overheat condition, not a potential fire), long into the cruise, without other confirming indications, does not demand a highdive and/or rapid slowing, to lower the landing gear, which may well not be possible, due to structural or performance considerations.