Fuel Dumping

[Heading 365]

A couple of questions which you might be able to help with.

Which commercial aircraft have fuel dumping systems?

If not which can land back at MTOW or have to burn fuel off?

Thanks for your help in anticipation.

Heading 365

[A-V-8R]

At my airline, the 757 and 767-200, and the ER versions cannot dump fuel and cannot legally, without exercising emergency authority, cannot be landed at MTOW.

Our Company:

757 MTOW 240 MLW 198

767-200 MTOW 322 MLW 272

Figure 8,500 burn holding 757, and about 10,500 burn for the 767-200, it can take a long time to get down to MLW during a time which you must, if one engine, land at the nearest suitable airport.

767-300 MTOW 407 MLW 320, and we can dump.

Overweight landings are allowed at our company, but no bank of 30 degrees and no autoland.

Inspection is required after an overweight landing, but time and extensiveness is based on softness/hardness of landing.

Other operators may have different numbers or limitations.

[SLT]

Our A330-200's have jettison facility as do, I believe, our 767-300's. I only know about the 330's though so I'll stick to them. It is an option on the A330 - our sister company's A330-300's don't have it for example.

A320/321/330 can all be landed up to MTOW, provided the QRH Overweight Landing Checklist is followed. This has a few points to it, the main one being that the touchdown must be achieved at less than 360 fpm. There are also some configuration and climb gradient points to think about. An overweight landing check may or may not follow, dependant on circumstances of the actual landing.

The A330 QRH Overweight Landing Checklist states -
"Automatic landing has been certified up to Max Landing Weight, but has been demonstrated in flight up to Max Take Off Weight. In determining the best course of action, the crew may consider the option to perform an automatic landing, provided the runway is approved for automatic landing".
This opens up a very interesting debate - To jettison or not to jettison???? As far as I can see - no right or wrong answer to this - have discussed it at length with various trainers and they've all agreed that it's personal preference. However, the general consensus seems to be that if time is critical - don't dump, and if it isn't time critical or runway length/weather is a factor - do dump. I think I'll start a little thread of my own on this!!!

Hope this helps. :)

[Draculas Teabag]

B744 (and the classic too!) can dump gas. If it's a max weight departure (397 ton) and you need to come back then, depending on your max landing weight (they vary 285 - 295 ton), you will need to lose about 100,000 kilos of kero. Time taken to dump would be about 55 minutes. If you didn't have the dump facility it would take many hours to burn the gas off!

If you don't have time to dump (e.g. you are on fire) then obviously you are going to have to land over the max landing weight, after which maintenance have to do a heavy landing check. As you can imagine at these weights you would chew a bit of runway and to make the problem worse the ref speeds at that weight are above 180 knots (max KIAS for flap 30) so you have to use flap 25. You can't do an autoland either. :(

[Heading 365]

Thanks for the replies they are very helpful, can anybody help with A340's, B777's, B737's and any others.

If anybody is wondering it is to help training ATCO's in handling unusual situations.

H365

[Lost_luggage34]

I will probably get shot down in flames here if you excuse the phrase. But back in my previous life, I understood that the only commercial a/c which could land with a full fuel uptake without too many issues was the 737.

Rather old information so am referring to the earlier series.

[cirrus01]

For the 777, (at least the -200 version)

Fuel Jettison rate with both nozzles and override/jettison pumps running (i.e. normal operation) the book figure is 2449 kg/min
It has two operation modes............

1. MLW

2. Manual mode



In MLW mode the aircraft calculates the amount to dump to bring it to MLW (max landing weight) clever eh ?

It even will stop dumping if it works out if the C. of G. will go too far foward during the dump.......bloodly clever eh ?

In manual mode you can select amount of fuel to remain.

[roundwego]

What are the rules concerning a/c location when fuel dumping? Is there a minimum altitude and must the a/c be over water? Does the fuel evaporate quickly before it reaches the ground or would a passing boat be showered in avtur? Often have wondered about this as a small a/c pilot never having had fuel jettison.

[cirrus01]

Several years ago I witnessed the "Peoples Express" 747-100 shortly after its T/O incident at LGW.

It came overhead my location at around 2-3 thousand feet on its way back to LGW. It was still dumping and the fuel vapour could be smelt within a couple of minutes.

Normally (if you can call a fuel dump normal ) it would have been over the sea, or at much greater height or both, but circumstances dictated otherwise in this case.

[Wycombe]

Not to forget the good old L1011 - it can dump. I know as I was pax'ing on one that did - quite spectacular it was too!

[Heading 365]

Roundwego

If I remember correctly you may dump fuel at any level over the sea but over land not below 4000ft in summer and 7000ft in winter, but in an emergency situation anything goes!

H365

[aluminum ovcst]

Airbus has certified the A340 for landing up to MTOW. No inspection is required if landing is normal (on main gear, no significant side loads, etc) up to 1.4g, about 360 fpm. The landing loads are recorded on the DFDR. They also recommend 5000 ft AGL min in order for fuel to evaporate as much as possible, and don't dump in a short holding pattern, as JET A will sink at about 500 fpm.

[Tex]

The EPA states that fuel dumping should be done at 6,000' MSL or greater. I'm just full of trivia.

[A320_Murray]

Hey,
What's the aircraft handling like on approach with all this fuel? Does the aircraft sit with it's nose high on approach? What about upon landing a gear collasped and soem caught on fire and you have all that fuel onboard? Is there limitations on go-around with all that fuel? I assume the engines N1's would be kept quite high in case of go-around, do wan tlong spool-up times do we? heheheh
Thanks in advance,

Regards,
Matthew

[CaptSnails]

A340-300 MTOW is 260T and max landing at 188T. As mentioned there is an overweight landing procedure in the QRH . However the aircraft can dump 1T per minute.

[pukeko]

Regarding altitude for fuel dumping, ICAO only says that it should not be less than 6000ft, anything else would be a local/company requirement.

ICAO refs also mention the possibility of aircraft going no-coms during dumping (switching off electrics) - how common is that? As a controller, that interests me!

I'd also be interested to hear any words of wisdom regarding the fuel vapour zone and how long it lasts. ICAO is telling us that it needs to be kept clear of other traffic for 15 minutes...

Cheers

[Heading 365]

The UK Manual of Air Traffic Services Part 1 staes with regard to fuel dumping that

a) over the sea if at all possible: or

b) above 10000ft agl.

Exceptionally, if a) or b) is impracticable or inconsistent with safety, fuel may be jettisoned above 7000ft agl in winter and 4000ft agl in summer. For fuel to be jettisoned below these levels the situation must be unavoidable.

A vertical separation of at least 1000ft between aircraft should be maintained.

H365

ps Thanks for all the info so far.

[Sky Goose]

I heard a tall story about a DC-8 in Hong Kong that needed to dump (fuel that is!), it was put in a hold, and decended in the hold while dumping.
Apparently it flew through its own vapour and exploded.:eek:
Sound like allot of bs to me. But you never know, anyone heard of this one?

ps what would happen if a jet engine ingested fuel vapour, just a bit of a surge I would imagine?

cheers