Change Forum... Civil Aviation Travel, Polls & Prefs Tech/Ops Aviation Hobby Aviation Photography Photography Feedback Trip Reports Military Av & Space Non-Aviation Site Related LIVE Chat My Starred Topics | Profile | New Topic | Forum Index | Help | Search
 Fuel Dumping And Max Landing Weight
 smartt1982 From United Kingdom, joined Nov 2007, 225 posts, RR: 0Posted Tue Jun 12 2012 13:54:42 UTC (3 years 11 months 2 weeks 3 days 1 hour ago) and read 5138 times:

 How does it work with regards to Max landing weight. My understanding is that aircraft require a fuel dumping system if their Max Take off weight is significantly higher than the Max Landing weight, does this always apply? I do know sometimes an aircraft may have to do an overweight landing and this would require as a minimum an inspection by maintenance. If an aircraft does NOT have a fuel dumping system does this mean that it HAS to be able to land overweight up to its Max take off weight?
 tdscanuck From Canada, joined Jan 2006, 12710 posts, RR: 78 Reply 1, posted Tue Jun 12 2012 14:12:19 UTC (3 years 11 months 2 weeks 3 days ago) and read 5131 times:

 Quoting smartt1982 (Thread starter):My understanding is that aircraft require a fuel dumping system if their Max Take off weight is significantly higher than the Max Landing weight, does this always apply?

Yes, although the definition of "significantly" moves around a bit.

 Quoting smartt1982 (Thread starter):If an aircraft does NOT have a fuel dumping system does this mean that it HAS to be able to land overweight up to its Max take off weight?

Yes, in the sense that all aircraft can land overweight up to their max takeoff weight. What varies is how much damage you're likely to do in the process.

Tom.

 Starlionblue From Greenland, joined Feb 2004, 17649 posts, RR: 65 Reply 2, posted Tue Jun 12 2012 18:23:26 UTC (3 years 11 months 2 weeks 2 days 20 hours ago) and read 5065 times:

 Quoting tdscanuck (Reply 1):Quoting smartt1982 (Thread starter): If an aircraft does NOT have a fuel dumping system does this mean that it HAS to be able to land overweight up to its Max take off weight? Yes, in the sense that all aircraft can land overweight up to their max takeoff weight. What varies is how much damage you're likely to do in the process.

To add to this, it's all a matter of how much risk you need to take in the particular situation.

If the plane is on fire, you land as soon as you can. In this case the risk of not landing is higher than the risk of landing overweight (fast).

If the gear does not come down, you are well served with lowering your weight. If you can dump, you dump. If you can't dump, you circle to burn off fuel.

As was mentioned in a previous thread, landing overweight is not a horrible thing to be avoided at all costs. It is a tool available to the pilots and should be used if the situation warrants it. If you have a fire in the hold, landing overweight and possibly dinging the aircraft is hardly your biggest problem.

 "There are no stupid questions, but there are a lot of inquisitive idiots."
 zeke From Hong Kong, joined Dec 2006, 10808 posts, RR: 76 Reply 3, posted Wed Jun 13 2012 00:05:29 UTC (3 years 11 months 2 weeks 2 days 15 hours ago) and read 4987 times:

 Quoting smartt1982 (Thread starter): My understanding is that aircraft require a fuel dumping system if their Max Take off weight is significantly higher than the Max Landing weight, does this always apply?

No, even with fuel dump feature, one needs to look at the possibility of needed to return immediately after takeoff, and fuel dumping is not fast enough to make that happen.

 Quoting smartt1982 (Thread starter):I do know sometimes an aircraft may have to do an overweight landing and this would require as a minimum an inspection by maintenance.

The type of inspection is normally related to the type of landing "seen" by the airframe, if it is low impact (less than say 300 ft/min) it would need a different inspection than high impact. A high impact landing at high weights could mean a gear change, even if the inspection found nothing.

 Quoting smartt1982 (Thread starter):If an aircraft does NOT have a fuel dumping system does this mean that it HAS to be able to land overweight up to its Max take off weight?

Normally a figure just under, that being the fuel burn-off to come back around for an immediate landing.

 We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 Goldenshield From United States of America, joined Jan 2001, 6170 posts, RR: 13 Reply 4, posted Wed Jun 13 2012 01:40:20 UTC (3 years 11 months 2 weeks 2 days 13 hours ago) and read 4970 times:

 Quoting zeke (Reply 3):The type of inspection is normally related to the type of landing "seen" by the airframe, if it is low impact (less than say 300 ft/min) it would need a different inspection than high impact.

Depending on the airframe, possibly no inspection at all.

 Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.
 SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 66 Reply 5, posted Wed Jun 13 2012 08:40:09 UTC (3 years 11 months 2 weeks 2 days 6 hours ago) and read 4883 times:

 Quoting smartt1982 (Thread starter):My understanding is that aircraft require a fuel dumping system if their Max Take off weight is significantly higher than the Max Landing weight

Common misconception. Under US FARs it goes like this. A transport category airplane is required to have a fuel jettisoning system (FAR 25.1001) unless it can meet the climb requirements of FAR 25.121(d) Note that this has absolutely nothing with structural damage considerations for landing. Nobody cares about that. It is about rejecting the landing with an engine inoperative and not crashing. 25.121(d) describes an ability to climb at a 2.1% (for two-engine airplane with an engine inoperative) which is 2.1 feet of elevation gained in 100 feet of horizontal travel. Again it has nothing to do with overweight landings.

Further, since the max ramp weight of a jet is always greater than the max landing weight it follows that it is okay for a plane to BE on the ground at that higher weight, therefore the only consideration is the impact speed with the ground at that higher weight. Since F=MA if you can get your vertical speed to near zero at touchdown you can land a plane at max ramp weight with no damage whatever.

 Happiness is not seeing another trite Ste. Maarten photo all week long.
 smartt1982 From United Kingdom, joined Nov 2007, 225 posts, RR: 0 Reply 6, posted Wed Jun 13 2012 13:45:05 UTC (3 years 11 months 2 weeks 2 days 1 hour ago) and read 4778 times:

 Cheers for the info. How come Boeing have installed the system on aircraft were it is not actually required?. Of course not disageeing or anything but just looked up those FAR requirements that you mentioned and they made mention of a number of aircraft were they have installed a dumping system but it is not actually required.
 SlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 66 Reply 7, posted Wed Jun 13 2012 14:45:18 UTC (3 years 11 months 2 weeks 2 days ago) and read 4764 times:

 Ah yes, customer options. If you buy an airframe with one set of operating weights you have those limits. If you would like, you can usually "buy" higher gross weights, in the form of performance charts and landing gear/wing spar inspection procedures for that same airplane. If you start increasing then 25.121(d) may eventually become a limitation on increasing weights, so for a few thousands per tail you can have the pipes and valves installed. Small penalty there - a few pounds of additional weight to carry around but you've removed one potential barrier to operating your plane at higher weights. I'd bet that all models have the possibility (courses for the pipes etc.) designed into them. It may also make the plane easier to sell, used, to whoever is going to operate it next, when it comes time to replace it with newer equipment. Airlines always have one eye to disposing of their old tails.
 Happiness is not seeing another trite Ste. Maarten photo all week long.
 Top Of Page Change Forum... Civil Aviation Travel, Polls & Prefs Tech/Ops Aviation Hobby Aviation Photography Photography Feedback Trip Reports Military Av & Space Non-Aviation Site Related LIVE Chat Forum Index

Reply To This Topic Fuel Dumping And Max Landing Weight
• 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.
• DETAILED RULES

 Similar topics: More similar topics...
About Takeoff Weight And Landing Weight posted Wed May 24 2000 06:21:28 by Samurai 777
Winglets And Max Altitude posted Thu Jun 9 2011 03:55:49 by smartt1982
Engine Failure, Vmc, And Max 5 Degrees Banking Ang posted Sat Oct 2 2010 09:23:25 by aerotech777
Md80 And DC9 Landing Gear? posted Sat Jul 31 2010 11:42:24 by b767
Fuel Dumping.... posted Wed Jul 14 2010 13:47:08 by steiner
Fuel Dumping Question posted Sat May 3 2008 13:52:02 by Orlando666
Pilots: Methods To Save Fuel (Safely And Legally)? posted Thu Jul 12 2007 22:44:15 by N231YE
Is This Fuel Dumping? posted Thu Oct 27 2005 07:01:42 by PUnmuth@VIE
Fuel Dumping On Ground? posted Mon Oct 3 2005 16:35:46 by 2H4
PW2040 Fuel Burn At Max Thurst At Takeoff posted Wed Sep 21 2005 21:41:27 by 9V-SPJ