Curious...Hot start?
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Curious...Hot start?
Interesting video I found. Could anyone enlighten me to what is going on here? Looks terrible but I don't know enough about jet engine starts to even guess. I have no further info on this video as I found it on another forum.
http://gassundertrykk.com/movie/engine-start.wmv
Thanks in advance
Eric
http://gassundertrykk.com/movie/engine-start.wmv
Thanks in advance
Eric
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Wow! That would have de-iced the wing! My guess is that the first start failed and the engine was not purged sufficiently before another? There is a Boeing recommended 'dry start cycle' for clearing excesss fuel from failed starts.
Impressive film.
Impressive film.
Have toolbox, will travel
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Howdy,
Looks to me like it could have been the first start after an MEC change (fuel control) They always seem to toss out some flames and take a while to come up to stabilized idle speed on the first start after we change one... I could be wrong though...
Looks to me like it could have been the first start after an MEC change (fuel control) They always seem to toss out some flames and take a while to come up to stabilized idle speed on the first start after we change one... I could be wrong though...
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Looks to me to the the first Idle Power Leak Check following an engine change,if the new engine has been in storage (engine preservation been done as per the manual) they will fire out lots of smoke and flames past the tail on the initial run.After a couple of seconds at stable idle the smoke and flames dissappear.Usually the Airport Fire Service appears wanting to hose everything down!
Regards DDG
Regards DDG
Could be that someone forgot to reset the igniter CBs after maintenance. Happened to me on a 1-11 once. I happened to be stood underneath it at the time holding the start valve open!!! The flight crew realised that the EGT wasn't moving, checked the CB panel and pushed them back in. WOOOOOOOOF!!!
Never moved so fast in my life.
Mind you considering that the 737 is being filmed suggests that they knew this was going to happen so ignore the above cobblers.
Never moved so fast in my life.
Mind you considering that the 737 is being filmed suggests that they knew this was going to happen so ignore the above cobblers.
Seems like that if the ignition wasn't on that the sheer force of the engine airflow while spooling up would clear out most of the fuel and that when it did light the woof would be brief.
The video seems to show a pronounced lingering of flame long after. I would suspect clogged fuel nozzles and drizzling rather than fogged fuel going back into the turbine.
The video seems to show a pronounced lingering of flame long after. I would suspect clogged fuel nozzles and drizzling rather than fogged fuel going back into the turbine.
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I've been away for the last two weeks, so i was unaware of the popularity this video had suddently gotten (it's apparently been posted on bulletins boards all over the web). It's starting to wear off now i suppose, but i assume some of you are still interessed in what's actually taking place on the video. There's alot of assuming, and allthough some is right, alot is also wrong.
First of all, there are no Pax on board the aircraft. We were three people in the cockpit (me, and an additional two) and two people outside (one of which filmed the clip). All of us are maintenance crew.
What is shown on the clip is what is known as an "wet run". The engine had just been installed (replacing an engine that was due for maintenance), and this is the first startup of the engine after a long storage period. Flames like this on wet runs are actually quite usual (or so i've heard), just not this big.
What happens during a wet run is that the engine burns out any residual oil inside the engine that was left there during the storage period. It also burns a certain amount of fuel because the engines usually ignite slower at first startups after storage. The thing that happened to us was that we didn't get any ignition on the first try, thus we filled the engine up with quite an amount of fuel. Before a second try, you're supposed to dryblow the engine with the starter to get the fuel out. That's where we got lazy and didn't do our job properly. On our second attempt, we poured fuel into the engine once again and when it finally ignited we got a result worthy of rememberance.
Some of you might find it unbelivable, but there was no damage to neither engine nor flaps after the incident. Normal on-installation test procedures were taken on the engine, and the plane left the airport with Pax on board the next day.
If anyone have any additional questions, you can reach me on [email protected]
Ps: The fact that it was filmed was a pure co-incident. We had no intentions on making any flame at all.
First of all, there are no Pax on board the aircraft. We were three people in the cockpit (me, and an additional two) and two people outside (one of which filmed the clip). All of us are maintenance crew.
What is shown on the clip is what is known as an "wet run". The engine had just been installed (replacing an engine that was due for maintenance), and this is the first startup of the engine after a long storage period. Flames like this on wet runs are actually quite usual (or so i've heard), just not this big.
What happens during a wet run is that the engine burns out any residual oil inside the engine that was left there during the storage period. It also burns a certain amount of fuel because the engines usually ignite slower at first startups after storage. The thing that happened to us was that we didn't get any ignition on the first try, thus we filled the engine up with quite an amount of fuel. Before a second try, you're supposed to dryblow the engine with the starter to get the fuel out. That's where we got lazy and didn't do our job properly. On our second attempt, we poured fuel into the engine once again and when it finally ignited we got a result worthy of rememberance.
Some of you might find it unbelivable, but there was no damage to neither engine nor flaps after the incident. Normal on-installation test procedures were taken on the engine, and the plane left the airport with Pax on board the next day.
If anyone have any additional questions, you can reach me on [email protected]
Ps: The fact that it was filmed was a pure co-incident. We had no intentions on making any flame at all.
Last edited by serv; 19th Apr 2004 at 14:11.
We always do a wet cycle first anyway. (after an engine change that is).
Let it drain for a few minutes, do a dry cycle for as long as possible (starter limits permitting), and then a full start.
Not a criticism but do your procedures not follow a similar pattern?
Let it drain for a few minutes, do a dry cycle for as long as possible (starter limits permitting), and then a full start.
Not a criticism but do your procedures not follow a similar pattern?
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Starter Limits
Hi Turin, any idea what the limits are on the PW 4056 or B777 Rolls ???.
Does it also have something to do with OAT???
Cheers,
HSD
Does it also have something to do with OAT???
Cheers,
HSD
Last edited by High Speed Descent; 23rd Apr 2004 at 14:09.