Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
I Thought Narrowbodies/B737s Couldn't Dump Fuel?  
User currently offlinePPVRA From Brazil, joined Nov 2004, 8873 posts, RR: 40
Posted (7 years 2 months 2 days 3 hours ago) and read 2759 times:

Was I mistaken or is there something not right in the following pic:


View Large View Medium
Click here for bigger photo!

Photo © Malcolm J.Bezzina




"If goods do not cross borders, soldiers will" - Frederic Bastiat
24 replies: All unread, jump to last
 
User currently offlineAvt007 From Canada, joined Jul 2000, 2132 posts, RR: 5
Reply 1, posted (7 years 2 months 2 days 3 hours ago) and read 2750 times:

If it is fuel, it may just be from a vent. It looks like they are climbing out, with a full fuel load.

User currently offlineKBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1
Reply 2, posted (7 years 2 months 2 days 3 hours ago) and read 2739 times:

Quoting Avt007 (Reply 1):
If it is fuel, it may just be from a vent.

It is streaming from the area of the fuel vent, so this is a possibility.

Kris



Proud to be an A&P!!!
User currently offlineMD11Engineer From Germany, joined Oct 2003, 13792 posts, RR: 63
Reply 3, posted (7 years 2 months 2 days 2 hours ago) and read 2723 times:

The flaps are extended, and the fog comes right from the O/B edge of the flap. I'd rather say that it is just condensation caused by the vortex at the edge of the O/B flap.

Jan


User currently offlineKBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1
Reply 4, posted (7 years 2 months 2 days 2 hours ago) and read 2710 times:

Quoting MD11Engineer (Reply 3):
I'd rather say that it is just condensation caused by the vortex at the edge of the O/B flap.

But if you look at the location where the fog starts, it is outboard of the O/B edge of the O/B flap, and it starts in the location of the fuel vent, which tells me it is coming from there.

Kris



Proud to be an A&P!!!
User currently offlineLTU932 From Germany, joined Jan 2006, 13864 posts, RR: 50
Reply 5, posted (7 years 2 months 2 days 2 hours ago) and read 2700 times:

If this was a fuel dump, wouldn't there have to be a nozzle somewhere on the trailing edge of the wing from where the fuel would be dumped?

User currently offlineDoug_Or From United States of America, joined Mar 2000, 3378 posts, RR: 3
Reply 6, posted (7 years 2 months 2 days 1 hour ago) and read 2693 times:

RE: narrowbodies, the 727 has dump capabilities, and I think other early jets did as well (707 DC-8, etc).


When in doubt, one B pump off
User currently offlineKBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1
Reply 7, posted (7 years 2 months 2 days ago) and read 2671 times:

Quoting LTU932 (Reply 5):
If this was a fuel dump, wouldn't there have to be a nozzle somewhere on the trailing edge of the wing from where the fuel would be dumped?

This is not a fuel dump. What most likely happened is that fuel epxanded in the tanks due to increased temperatures and simply overlowed throught the fuel tank vent on the outboard wing. It happens often, and I have witnessed it several times. It even happens all the time on light aircraft.

Kris



Proud to be an A&P!!!
User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 8, posted (7 years 2 months 1 day 23 hours ago) and read 2658 times:

Looks like Vapours emmitting from the Fuel Vent.Looks like the Aircraft was fuelled to capacity & the Expansion due Temp rise has caused the Spillege.Can occur on Ground too.
regds
MEL



Think of the brighter side!
User currently offlinePPVRA From Brazil, joined Nov 2004, 8873 posts, RR: 40
Reply 9, posted (7 years 2 months 1 day 16 hours ago) and read 2557 times:

Interesting, thanks guys! Didn't know of the existence of fuel vents till now.


"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 10, posted (7 years 2 months 1 day 14 hours ago) and read 2506 times:

Quoting PPVRA (Reply 9):
Didn't know of the existence of fuel vents till now.

Fuelers love them since they sometimes get to take impromptu showers while standing under them. Big grin



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineCitationJet From United States of America, joined Mar 2003, 2368 posts, RR: 3
Reply 11, posted (7 years 2 months 1 day 13 hours ago) and read 2456 times:

According to Boeing Website the following fuel jettison capability:
http://www.boeing.com/commercial/airports/faqs/fueldump.pdf

707 - yes
717 - no
720 - yes
727 - yes
737 - no
BBJ - no
747 - yes
757 - no
767-200/300 - **
767-400 - yes
777 - yes
787 - yes
DC-8 - yes
DC-10 - yes
MD-11 - yes
MD-80 - no
MD-90 - no

** Early models did not have fuel jettison capability, although airlines could install capability. Later models had jettison capability.



Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
User currently offlineLTU932 From Germany, joined Jan 2006, 13864 posts, RR: 50
Reply 12, posted (7 years 2 months 1 day 12 hours ago) and read 2420 times:

Quoting KBFIspotter (Reply 7):
This is not a fuel dump.

That was the same conclusion I got to, hence my question, just to be sure.


User currently offlineTristarSteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 13, posted (7 years 2 months 1 day 12 hours ago) and read 2407 times:

Quoting PPVRA (Reply 9):
Interesting, thanks guys! Didn't know of the existence of fuel vents till now.

Fuel vent is not really the right word for them. They are fuel tank air vents.
On the ground when fuel is being pumped into the tanks, the displaced air comes out of here.
In flight the fwd facing NACA duct provides a slight (about 2psi) positive pressure on the fuel in the tanks.
During refuelling, if something goes wrong, fuel can end up in the vent surge tank at the wingtip. This usually hols only air, but it has been known for crews to put a couple of hundred kilos of fuel in there for a very long range flight. (illegally!) It is this fuel which you can see venting on take off in the picture. I have seen it happen with a US registered B757 leaving Europe.
The B747 is partcularly prone to this on the ramp because as the wing bends down with a full load of fuel, the vent intake ends up at the lowest point in the tank! The wing rises during the take off roll so in flight it is higher up. (Never try and store fuel in here on a B747)


User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 25
Reply 14, posted (7 years 2 months 1 day 12 hours ago) and read 2399 times:

Quoting KBFIspotter (Reply 2):
It is streaming from the area of the fuel vent, so this is a possibility.

The fuel tank air vent is much, much more closer to the wingtips than that location in the pic. Its probably about 10-12" or so from the wingtips.

Quoting KBFIspotter (Reply 7):
This is not a fuel dump.

 checkmark 



A Safe Flight Begins With Quality Maintenance On The Ground.
User currently offlineGQfluffy From , joined Dec 1969, posts, RR:
Reply 15, posted (7 years 2 months 1 day 11 hours ago) and read 2374 times:

I'd say someone just used one of the lavs...

User currently offline747400sp From United States of America, joined Aug 2003, 3301 posts, RR: 2
Reply 16, posted (7 years 2 months 1 day 3 hours ago) and read 2265 times:

Quoting CitationJet (Reply 11):
According to Boeing Website the following fuel jettison capability:
http://www.boeing.com/commercial/airports/faqs/fueldump.pdf

707 - yes
717 - no
720 - yes
727 - yes
737 - no
BBJ - no
747 - yes
757 - no
767-200/300 - **
767-400 - yes
777 - yes
787 - yes
DC-8 - yes
DC-10 - yes
MD-11 - yes
MD-80 - no
MD-90 - no

** Early models did not have fuel jettison capability, although airlines could install capability. Later models had jettison capability.

Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason.


User currently offlineDw747400 From United States of America, joined Aug 2001, 1254 posts, RR: 1
Reply 17, posted (7 years 2 months 1 day 3 hours ago) and read 2255 times:

Quoting 747400sp (Reply 16):
Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason.

It is perfectly safe... depending on the nature of the emergency the aircraft can either hold for a few hours, or make an overweight landing. Remember, the narrow-bodies have significantly less fuel aboard than a heavy on an international flight.



CFI--Certfied Freakin Idiot
User currently offlineKBFIspotter From United States of America, joined May 2005, 729 posts, RR: 1
Reply 18, posted (7 years 2 months 1 day 2 hours ago) and read 2249 times:

Quoting AirframeAS (Reply 14):
The fuel tank air vent is much, much more closer to the wingtips than that location in the pic. Its probably about 10-12"

Actually on the 733 thru 735, it is about four to five feet from the wing tip. The area outboard the fuel vent is three interconected open bays. On WN mx task cards, these three bays are refered to as TAI exhaust bays.

http://www.b737.org.uk/fueltankvent.jpg
Here is a photo of the vent in question... The fuel tank vent is on the left, and on the right is the surge tank pressure relief valve. The fuel vent is outboard in this photo of the right wing of a 735. The wing tip is another four to five feet outboard from the vent.

http://www.b737.org.uk/surge_tank_venting.jpg
Here is a similar photo of the one in question... the mist is coming from the same location as in the one above.

Kris



Proud to be an A&P!!!
User currently offlineL-188 From United States of America, joined Jul 1999, 29690 posts, RR: 59
Reply 19, posted (7 years 2 months 1 day 2 hours ago) and read 2248 times:

I agree with the others who say it is vapor comming out of a vent.

Back to the original question, AFAIK (without looking up the specific reg) is that any aircraft that has a MTOW heavier their the MLW is required to have the capability to dump fuel so that in an emergency it can make a landing at a weight below the MTOW.

The spread between MTOW and MLW generally is wider on longer legged aircraft, sometimes adding up thousands (tens of?) pounds of difference.



OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 20, posted (7 years 2 months 1 day 1 hour ago) and read 2242 times:

Quoting L-188 (Reply 19):
Back to the original question, AFAIK (without looking up the specific reg) is that any aircraft that has a MTOW heavier their the MLW is required to have the capability to dump fuel so that in an emergency it can make a landing at a weight below the MTOW.

Excerpted from: http://en.wikipedia.org/wiki/Fuel_dumping. Most of it is my writing...

As jets began flying with U.S. airlines in the late 1950s and early 1960s, the FAA rule in effect at the time mandated that if the difference between an aircraft's maximum structural takeoff weight and its maximum structural landing weight was greater than 105%, the aircraft had to have a fuel dump system installed. Accordingly, aircraft such as the Boeing 707 and 727, and Douglas DC-8 had fuel dump systems. Any of those aircraft needing to return to a takeoff airport above the maximum structural landing weight would simply jettison an amount of fuel sufficient to reduce the aircraft's total weight to below that maximum structural landing weight limit, and then land.

During the 1960s, Boeing introduced the 737, and Douglas the DC-9, the original models of each being for shorter routes, and the 105% figure was not an issue, thus they had no fuel dump systems installed. During the 1960s and 1970s, both Boeing and Douglas "grew" their respective aircraft as far as operational capabilities were concerned via Pratt and Whitney's development of increasingly powerful variants of the JT8D engines that powered both aircraft series. Both aircraft were now capable of longer duration flights, with increased weight limits, and complying with the existing 105% rule became problematic due to the costs associated with adding a fuel dump system to aircraft in production. Considering the more powerful engines that had been developed, the FAA changed the rules to delete the 105% requirement, and FAR 25.1001 was enacted stating a jettison system was not required if the climb requirements of FAR 25.119 (Landing Climb) and FAR 25.121 (Approach Climb) could be met, assuming a 15-minute flight. In other words, for a go-around with full landing flaps and all engines operating, and at approach flap setting and one engine inoperative, respectively.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 16908 posts, RR: 67
Reply 21, posted (7 years 2 months 19 hours ago) and read 2194 times:

Quoting 747400sp (Reply 16):
Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason.

I think you are assuming that fuel dump capability is installed to decrease the risk of fire/explosion during an emergency landing. This is not the case. If the plane is about to crash into the ground no amount of fuel dumping will change the situation.

It is installed to decrease landing weight for an emergency early in the flight. For a narrowbody, this is not needed. Also, a narrowbody can simply fly around and burn off fuel in some cases. This would take too long in a widebody.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 22, posted (7 years 2 months 6 hours ago) and read 2105 times:

Quoting TristarSteve (Reply 13):
The B747 is partcularly prone to this on the ramp because as the wing bends down with a full load of fuel, the vent intake ends up at the lowest point in the tank! The wing rises during the take off roll so in flight it is higher up. (Never try and store fuel in here on a B747)

Wasn't there a Similar Incident a few years ago where Pax refused to fly an Airline after Fuel poured out of the Vents during Taxi Twice.

Quoting 747400sp (Reply 16):
Wow ! How dangerous, any jetliner should be able to jettison fuel for safety reason



Quoting L-188 (Reply 19):
any aircraft that has a MTOW heavier their the MLW is required to have the capability to dump fuel so that in an emergency it can make a landing at a weight below the MTOW.

 bigthumbsup 

regds
MEL



Think of the brighter side!
User currently offlineAirframeAS From United States of America, joined Feb 2004, 14150 posts, RR: 25
Reply 23, posted (7 years 1 month 3 weeks 6 days 14 hours ago) and read 1921 times:

Quoting KBFIspotter (Reply 18):
Actually on the 733 thru 735, it is about four to five feet from the wing tip.

Thats about right. I just didnt have my 734 manual in front of me from AS. But close enough.



A Safe Flight Begins With Quality Maintenance On The Ground.
User currently offlineHAWK21M From India, joined Jan 2001, 31568 posts, RR: 57
Reply 24, posted (7 years 1 month 3 weeks 2 days 20 hours ago) and read 1721 times:

http://www.b737.org.uk/fuel_tank_vent.htm
regds
MEL

[Edited 2007-02-24 12:35:12]


Think of the brighter side!
Top Of Page
Forum Index

Reply To This Topic I Thought Narrowbodies/B737s Couldn't Dump Fuel?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Why Not The Fuel Dump Option In The B6 A320? posted Thu Sep 22 2005 17:37:21 by Bongo
Fuel Dump Subsys - Optional? posted Wed Oct 6 2004 02:22:26 by Gigneil
Minimum Fuel Dump Altitude? posted Fri Mar 19 2004 18:54:42 by FutureCGNPilot
Fuel Dump Question posted Mon Dec 1 2003 21:16:38 by Levg79
A330 Fuel Dump Vent Question? posted Wed Aug 14 2002 18:16:34 by Mr Spaceman
B767-200 Fuel Dump? posted Mon May 13 2002 04:56:49 by UAL Bagsmasher
Fuel Transfer On B737s posted Sun Apr 14 2002 00:58:24 by Mikeclod
Fuel Dump Specs posted Mon Nov 19 2001 02:06:16 by Worldaero
B777 Fuel-Cost Over A340 Fuel-Cost posted Wed Feb 7 2007 20:51:25 by Bmacleod
Question About Airline Fuel.... posted Sun Jan 28 2007 19:19:15 by Scalebuilder

Sponsor Message:
Printer friendly format