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Backfire While Starting WN Jet At LAX Today  
User currently offline747hogg From , joined Dec 1969, posts, RR:
Posted (8 years 3 months 3 days 11 hours ago) and read 8599 times:

This must be a normal thing to the seasoned flyer, but it rocked my friggin' world! I was sitting next to #2 and as they were starting it up a big pop followed by a flash of flame shot out.. The A/C took on the smell of jet fuel for a few seconds as well. It kept right on spooling up to speed and no one said anything. For a split second I was honestly looking for an emergency door to head for. Normal? I've never seen this happen before.

28 replies: All unread, showing first 25:
 
User currently offlineIkramerica From United States of America, joined May 2005, 21562 posts, RR: 59
Reply 1, posted (8 years 3 months 3 days 11 hours ago) and read 8582 times:

Never seen it before in all my flights. I assume that since you went on your way, the ground crew and the flight crew didn't think it was a problem.

Sugar in the fuel tank? Potato in the tailpipe?  Wink



Of all the things to worry about... the Wookie has no pants.
User currently offlineFr8Mech From United States of America, joined Sep 2005, 5599 posts, RR: 15
Reply 2, posted (8 years 3 months 3 days 11 hours ago) and read 8574 times:

Jet engines do not backfire, they compressor stall or surge. Was the flame out the front or rear? Out the front indicates a stall or surge, bad news. Out the back indicates an ignition system that was late igniting the fuel in the cans or some maintenance was done on the engine which required a wet motor and the engine wasn't cleared completely, no worries, probably.


When seconds count...the police are minutes away.
User currently offlineQXatFAT From Israel, joined Feb 2006, 2405 posts, RR: 5
Reply 3, posted (8 years 3 months 3 days 11 hours ago) and read 8560 times:

Quoting Ikramerica (Reply 1):
Sugar in the fuel tank? Potato in the tailpipe?

Ahh my good ol high school years. But wait, that was just 4 years ago!

Quoting Fr8Mech (Reply 2):
Out the back indicates an ignition system that was late igniting the fuel in the cans or some maintenance was done on the engine which required a wet motor and the engine wasn't cleared completely, no worries, probably.

Wow thank you. I have been trying to figure out why that happend on one of my flights out of ABQ on WN one time. Never thought of this. Thank you for posting this answer!



Don't Tread On Me!
User currently offline777WT From United States of America, joined Jan 2005, 877 posts, RR: 1
Reply 4, posted (8 years 3 months 3 days 7 hours ago) and read 8433 times:

Quoting Fr8Mech (Reply 2):
or some maintenance was done on the engine which required a wet motor and the engine wasn't cleared completely

a FADEC or a FCU change which requires wet motoring to clear out the storage oil inside of them.


User currently offlineEMBQA From United States of America, joined Oct 2003, 9364 posts, RR: 11
Reply 5, posted (8 years 3 months 3 days 6 hours ago) and read 8361 times:

Quoting 747hogg (Thread starter):
Normal? I've never seen this happen before.

Very normal. It sounds like the crew did a residual start. That means the engine was too hot to do a standard start. They start the engine spooling with ignition off. This sucks in cool air and drops the ITT. You then introduce fuel and then a few seconds later add the ignition. Sometimes you get a surge at light off and a fuel small as the residual fuel burns off.



"It's not the size of the dog in the fight, but the size of the fight in the dog"
User currently offlineContrails From United States of America, joined Oct 2000, 1834 posts, RR: 0
Reply 6, posted (8 years 3 months 3 days 2 hours ago) and read 8169 times:

I saw this happen on an Eastern DC-9 at DCA not long before the carrier went under. It shot a flame back a good 10 feet, maybe more. I was on the Metro platform, probably a hundred feet or so away, when it happened. I'm glad nobody was behind it.

That's the only time I've seen something like that.



Flying Colors Forever!
User currently offlineLuketenley From United States of America, joined Jul 2006, 419 posts, RR: 1
Reply 7, posted (8 years 3 months 3 days 2 hours ago) and read 8162 times:

I saw this on a Delta MD80 a few months back. I assume it doesn't affect the engine or flight because it took off normal.


Pittsburgh International Airport lover
User currently offlineAogdesk From United States of America, joined Jun 2004, 935 posts, RR: 3
Reply 8, posted (8 years 3 months 3 days 2 hours ago) and read 8142 times:

Watching an L1011 with RB211's was always a treat, seemed to happen alot, must've scared the daylights out of pax who happened to be checking out the tailpipe on engine start.

User currently offlineYhz78 From Canada, joined Apr 2004, 147 posts, RR: 0
Reply 9, posted (8 years 3 months 3 days 1 hour ago) and read 8080 times:

Another good plane for this sort of thing is the F28's. Especially a kickstart flight in -15C conditions.


Canada Rocks! From the west coast to the best coast!
User currently offlineMD88Captain From United States of America, joined Nov 2001, 1335 posts, RR: 20
Reply 10, posted (8 years 3 months 3 days 1 hour ago) and read 8080 times:

It just isn't a big deal. At night, directly in back of an aircraft, one can look into the engine and see it light off. Sometimes it throws more flame than other times. And if there is residual flame in the engine you can get it to torch off. Again, no big deal. You will not even know about it in the cockpit.

User currently offlineBarney Captain From United States of America, joined Nov 2001, 982 posts, RR: 12
Reply 11, posted (8 years 3 months 2 days 22 hours ago) and read 7890 times:

Quoting EMBQA (Reply 5):
It sounds like the crew did a residual start. That means the engine was too hot to do a standard start. They start the engine spooling with ignition off. This sucks in cool air and drops the ITT. You then introduce fuel and then a few seconds later add the ignition.

Good call EMB, but on the 737 at least, the ignition and fuel are both controlled by the start lever. There really isn't an effective way (short of pulling cb's) to separate the two. If we have high residual EGT, we simply motor the engine until it drops below 200 degrees, then light it off. You bring back fond memories though, the residual start you described is exactly the way we did it in the Metroliner....



...from the Banana Republic....
User currently offlineBroke From United States of America, joined Apr 2002, 1322 posts, RR: 3
Reply 12, posted (8 years 3 months 2 days 21 hours ago) and read 7786 times:

Fire out of the tail pipe during starting of a turbine engine is called "torching". There maybe other reasons, but the most common cause is ignition of residual fuel that puddled in the tail pipe before the engine igniters (they are not spark plugs) are turned on. When the engine lights off, it can get the tailpipe hot enough to ignite the fuel and you get a flash of fire. It can happen on both jet engines and turboprop engines.
Torching has been experienced, at times, on an grander scale when the fuel shut off valve leaks and a considerable amount of fuel is in the turbine and tail pipe. This will cause a significant tongue of flame which can be very alarming to the causal observer. Usually continuing the engine start sequence will result in the flame going away due to airflow and the burning up of the residual fuel. Torching rarely causes any damage to the engine or airframe.


User currently offline747hogg From , joined Dec 1969, posts, RR:
Reply 13, posted (8 years 3 months 2 days 19 hours ago) and read 7661 times:

Thanks, the puff of fire was out the back, but the A/C had a fuel smell for a few seconds as well.

User currently offlineIkramerica From United States of America, joined May 2005, 21562 posts, RR: 59
Reply 14, posted (8 years 3 months 2 days 17 hours ago) and read 7540 times:

Quoting 747hogg (Reply 13):
Thanks, the puff of fire was out the back, but the A/C had a fuel smell for a few seconds as well.

no expert, but smells usually come from incomplete combustion, and what is being described above would likely result in incomplete combustion of the "pooled" fuel, as it just gets hot enough to ignite, but not hot enough to burn it off completely.



Of all the things to worry about... the Wookie has no pants.
User currently offlineDLAgent From United States of America, joined Apr 2006, 51 posts, RR: 0
Reply 15, posted (8 years 3 months 2 days 17 hours ago) and read 7531 times:

In the days of the L1011, we would experience that and it became a common occurance. They always had such a low whining sound, for about 45 seconds, it almost sounded as though they were hesitant to leave.

User currently offlineArluna From United States of America, joined Jun 2006, 88 posts, RR: 1
Reply 16, posted (8 years 3 months 2 days 16 hours ago) and read 7060 times:

The combustion chamber drain valve could have been stuck allowing fuel to puddle in the bottom of the combustion chamber.

The Chinook that I crewed in Viet Nam had an APU that had an intermittantly sticky drain valve and it was a spectacular sight to see at night when a ten foot flame would shoot out the back of the aft pylon. We had a team of civilian contract maintenance folks from Lear Seigler who refused to get on the helicopter when they saw it, we left them on the ramp to find another way to their destination.

Jerry


User currently offlineSteeler83 From United States of America, joined Feb 2006, 9262 posts, RR: 21
Reply 17, posted (8 years 3 months 2 days 16 hours ago) and read 6899 times:

Quoting Ikramerica (Reply 1):
Potato in the tailpipe?

*mocking* I'm not falling for the banana in the tailpipe?

-Eddie Murphy, Beverly Hills Cop  Smile

Now that is what I'd call one baked  flamed potato



Do not bring stranger girt into your room. The stranger girt is dangerous, it will hurt your life.
User currently offlineHAWK21M From India, joined Jan 2001, 31702 posts, RR: 56
Reply 18, posted (8 years 3 months 2 days 16 hours ago) and read 6836 times:

Quoting Fr8Mech (Reply 2):
Out the back indicates an ignition system that was late igniting the fuel in the cans or some maintenance was done on the engine which required a wet motor and the engine wasn't cleared completely, no worries, probably.

Also can be contributed by what RPM did the Pilot Introduce Fuel.Was it earlier than required.

Quoting Broke (Reply 12):
Fire out of the tail pipe during starting of a turbine engine is called "torching"


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regds
MEL



Think of the brighter side!
User currently offlineGilligan From , joined Dec 1969, posts, RR:
Reply 19, posted (8 years 3 months 2 days 15 hours ago) and read 6492 times:

Memories...dah dah dah dah dah dah......

I remember pushing out the silver anniversary bird and watching the number 1 smoke like a barbeque. Called the cpt on the headset and reported the smoke. He said, ok, how this? About then a tongue of flame shot out the rear end of the engine almost all the way back to the tail accompanied but a large "TONK". Before we got to the disconnect point the cpt asked if we could drag him back to the gate, somebody wanted off. Somebody turned into about 6 or 7.

Working on the ramp for CO I got completely used to seeing the EMB's torch on a regular basis. Especially when it was cold outside. Since the tailpipes are in the back out of view, never had to drag one back but it's a pretty impressive sight.


User currently offlineLPLAspotter From Portugal, joined Jan 2005, 682 posts, RR: 1
Reply 20, posted (8 years 3 months 2 days 3 hours ago) and read 5157 times:

Quoting Aogdesk (Reply 8):
Watching an L1011 with RB211's was always a treat, seemed to happen alot, must've scared the daylights out of pax who happened to be checking out the tailpipe on engine start.

Man those things would pour out smoke. Even the new ones did that. One time on a TWA L1011 they made an announcement that this would happen so nobody would freak out.

LPLAspotter



Nuke the Gay Wales for Christ
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 21, posted (8 years 3 months 2 days 3 hours ago) and read 5133 times:

Quoting LPLAspotter (Reply 20):
Man those things would pour out smoke. Even the new ones did that. One time on a TWA L1011 they made an announcement that this would happen so nobody would freak out.

If memory serves, Delta had an L10 on the taxiway at DFW some years ago, in queue for departure and started one (either #1 or #3) that had been shut down to conserve fuel. Typical RB211 smoke/torch, and someone indeed freaked and commenced a passenger-initiation evacuation. I don't recall how many people joined him/her (it was several) but it's easy to understand the human nature aspect of bailing out first and asking questions later.


User currently offlineAirfoilsguy From , joined Dec 1969, posts, RR:
Reply 22, posted (8 years 3 months 2 days 2 hours ago) and read 5087 times:

was it sorta like this?





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User currently offlineLPLAspotter From Portugal, joined Jan 2005, 682 posts, RR: 1
Reply 23, posted (8 years 3 months 2 days 1 hour ago) and read 5040 times:

There's a great video on flightlevel350.net of a IB 747 experiencing a compressor stall on takeoff from ORD. Here it is: http://www.flightlevel350.com/Aircra...ne_Iberia_Aviation_Video-1652.html

LPLAspotter



Nuke the Gay Wales for Christ
User currently offlineHAWK21M From India, joined Jan 2001, 31702 posts, RR: 56
Reply 24, posted (8 years 3 months 1 day 10 hours ago) and read 4877 times:

Quoting Airfoilsguy (Reply 22):
was it sorta like this

Wonder what the EGT was like  Smile
regds
MEL



Think of the brighter side!
25 Lucky42 : It is quite common on the DC-9/MD-80 aircraft. You open the start valve and motor the engine then throw the fuel lever and forget that you didn't turn
26 777WT : I was waiting to watch an ERJ-145 shoot flames out the back once. It never occured tho. It was a airstart due to a deferred APU. Engine attempted to
27 DTWAGENT : I've seen it happen and the first time I left a mess in my pants. After that I was ok with it. Of course I was 7 yrs old when I first saw this happen.
28 Jeb94 : Reminds me of a night on the ramp in MKE. A DC9-30 had just pushed off and was starting up. A lot of vapor poured out of the #2 engine followed by a h
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