General questions for pilots here

pulling is here occasionally. Think there was commercial pilot (Muddy Waters?) back on tTurd that signed in here years ago then disappeared.
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A Delta flight headed to Seoul, South Korea had to dump fuel and return to Detroit Metropolitan Airport today after a light in the cockpit indicated there possibly was an open maintenance panel on the outside of the aircraft, a spokesman for the airline said.

Flight 159 took off from Detroit at 4:48 p.m. and about 30 minutes later the indicator light came on, Delta spokesman Trebor Banstetter said.

He said the plane, which had 375 passengers on board, circled Lake Michigan, dumping fuel for about an hour in order to help ensure a safe landing, which it did shortly before 7 p.m.

"They landed safely without incident," Banstetter said.

He said the plane was going to be looked at by maintenance and the airline is exploring options to accommodate passengers.

Delta plane dumps fuel over Lake Michigan, returns to DTW shortly after takeoff

Have a few questions about the above story:

Why would an open maintenance panel door be cause to dump many thousands of pounds of fuel before landing?
If the door issue was considered severe enough to dump the fuel, why not land at the closest airport? O'Hare?
Why was the fuel dumped over the lake? What happens to dumped fuel? Had previously thought it evaporated before hitting the ground.

Good questions.

Ask the Dutch King:

The Dutch king has been leading a secret double life as an airline pilot for 21 years

I have no idea, but I'm usually on autopilot.

Couldn't find how many gallons of fuel were dumped?

Lake Michigan has an estimated volume measured on quadrillion's of gallons so if a plane is going to dump fuel it appears over one of the Great Lakes is the best spot for fuel that doesn't evaporate on the way down.

The Pantry wrote:pulling is here occasionally.  Think there was commercial pilot (Muddy Waters?) back on tTurd that signed in here years ago then disappeared.
_______________

A Delta flight headed to Seoul, South Korea had to dump fuel and return to Detroit Metropolitan Airport today after a light in the cockpit indicated there possibly was an open maintenance panel on the outside of the aircraft, a spokesman for the airline said.

Flight 159 took off from Detroit at 4:48 p.m. and about 30 minutes later the indicator light came on, Delta spokesman Trebor Banstetter said.

He said the plane, which had 375 passengers on board, circled Lake Michigan, dumping fuel for about an hour in order to help ensure a safe landing, which it did shortly before 7 p.m.

"They landed safely without incident," Banstetter said.

He said the plane was going to be looked at by maintenance and the airline is exploring options to accommodate passengers.

Delta plane dumps fuel over Lake Michigan, returns to DTW shortly after takeoff

Have a few questions about the above story:

Why would an open maintenance panel door be cause to dump many thousands of pounds of fuel before landing?
If the door issue was considered severe enough to dump the fuel, why not land at the closest airport?  O'Hare?
Why was the fuel dumped over the lake?  What happens to dumped fuel?  Had previously thought it evaporated before hitting the ground.

Wild ass guesses here:

Why would an open maintenance panel door be cause to dump many thousands of pounds of fuel before landing?
There had to be a risk of crash landing. Maybe they feared the landing gear wouldn't deploy.

If the door issue was considered severe enough to dump the fuel, why not land at the closest airport?  O'Hare?
O'Hare is crazy busy. Maybe it was easier for them to do a 180 back to Detroit instead of clearing a path for an emergency landing to get to ORD.

Why was the fuel dumped over the lake?  What happens to dumped fuel?  Had previously thought it evaporated before hitting the ground.
It won't land on any houses, or start any fires. Although it's still pretty wet around here. Dunno about it evaporating before it hits the ground.

All the fuel is contained in a special bladder, so once it's dumped, the airline goes to collect it. That bladder is made in New York by Kramerica Industries.

I don't know.

Decided to do some farting around, lookin' up stuff.  Not sure what plane was involved yesterday so went looking for something that would hold at least 375 passengers and could travel from Detroit to Seoul (surprisingly, only 6600 miles) without refueling.  Picked a Boeing 777-300ER (fuck Airbus).

Maximum takeoff weight:  775,000 pounds
Fuel capacity:  47,890 gallons...or approximately 300,000 pounds

Those weight numbers raised another question:  How thick is concrete on commercial runways and tarmacs?

The Pantry wrote:Decided to do some farting around, lookin' up stuff.  Not sure what plane was involved yesterday so went looking for something that would hold at least 375 passengers and could travel from Detroit to Seoul (surprisingly, only 6600 miles) without refueling.  Picked a Boeing 777-300ER (fuck Airbus).

Maximum takeoff weight:  775,000 pounds
Fuel capacity:  47,890 gallons...or approximately 300,000 pounds

Those weight numbers raised another question:  How thick is concrete on commercial runways and tarmacs?

Congrats, based on your internet searches you've qualified for the no fly list.

Floyd Robertson wrote:

The Pantry wrote:Decided to do some farting around, lookin' up stuff.  Not sure what plane was involved yesterday so went looking for something that would hold at least 375 passengers and could travel from Detroit to Seoul (surprisingly, only 6600 miles) without refueling.  Picked a Boeing 777-300ER (fuck Airbus).

Maximum takeoff weight:  775,000 pounds
Fuel capacity:  47,890 gallons...or approximately 300,000 pounds

Those weight numbers raised another question:  How thick is concrete on commercial runways and tarmacs?

Congrats, based on your internet searches you've qualified for the no fly list.

Good thing I don't care much for flying anymore.

The Pantry wrote:Decided to do some farting around, lookin' up stuff.  Not sure what plane was involved yesterday so went looking for something that would hold at least 375 passengers and could travel from Detroit to Seoul (surprisingly, only 6600 miles) without refueling.  Picked a Boeing 777-300ER (fuck Airbus).

Maximum takeoff weight:  775,000 pounds
Fuel capacity:  47,890 gallons...or approximately 300,000 pounds

Those weight numbers raised another question:  How thick is concrete on commercial runways and tarmacs?

Probably around 24" plus a gravel and sand subbase. They dump the fuel so if they do have a problem landing they don't take out half the airport. Usually fuel load is calculated so there's not a whole helluva lot of fuel left when they get to the destination.

Jake from State Farm wrote:

The Pantry wrote:Decided to do some farting around, lookin' up stuff.  Not sure what plane was involved yesterday so went looking for something that would hold at least 375 passengers and could travel from Detroit to Seoul (surprisingly, only 6600 miles) without refueling.  Picked a Boeing 777-300ER (fuck Airbus).

Maximum takeoff weight:  775,000 pounds
Fuel capacity:  47,890 gallons...or approximately 300,000 pounds

Those weight numbers raised another question:  How thick is concrete on commercial runways and tarmacs?

Probably around 24" plus a gravel and sand subbase. They dump the fuel so if they do have a problem landing they don't take out half the airport. Usually fuel load is calculated so there's not a whole helluva lot of fuel left when they get to the destination.

With as fucked up as most truck-trafficked Michigan roads are, you'd think some smart guy would suggest rebuilding them with a deeper base.

I'll chime in when I get to a keyboard.

Q: Why would an open maintenance panel door be cause to dump many thousands of pounds of fuel before landing?

Aircraft have a maximum landing weight(almost always less than the max takeoff weight), landing above that can result in such things as collapsed landing gear, cartwheeling down the runway, etc. When aircraft fly around to burn off fuel or dump fuel that is why. As far as the open panel there are dozens of them on a large aircraft, any of which could have the door rip off in flight and cause more damage(sucked into the engine and destroying it, severing hydraulics, etc). In case of an "emergency" like this one they would prefer to keep the aircraft near it's point of origin vs flying over a populated area in case of the worst case. Also from the airlines point of view it is a lot easier to get another airplane and crew setup from the hub to get the passengers on their way.

As far as the dumped fuel it usually atomizes into the atmosphere(the dumping mechanism is designed for that. Also (usually) you have to be above a certain altitude to be able to dump fuel AND they usually do it over un-populated areas(like a very large body of water). The dumped fuel is happening over a very large area and with the airplane moving very fast through the air so it is very well spread out. The fuel molecules are too small to precipitate and cling to other things in the air, usually ending up in clouds, then rain/hail/snow/ice).

PS also not all planes are designed to simply "dump" the fuel and will have to actually fly it off.

Here is the flight in question, looks like Wisconsin got the gas:

pulling69 wrote:Q: Why would an open maintenance panel door be cause to dump many thousands of pounds of fuel before landing?

Aircraft have a maximum landing weight(almost always less than the max takeoff weight), landing above that can result in such things as collapsed landing gear, cartwheeling down the runway, etc. When aircraft fly around to burn off fuel or dump fuel that is why. As far as the open panel there are dozens of them on a large aircraft, any of which could have the door rip off in flight and cause more damage(sucked into the engine and destroying it, severing hydraulics, etc). In case of an "emergency" like this one they would prefer to keep the aircraft near it's point of origin vs flying over a populated area in case of the worst case. Also from the airlines point of view it is a lot easier to get another airplane and crew setup from the hub to get the passengers on their way.

As far as the dumped fuel it usually atomizes into the atmosphere(the dumping mechanism is designed for that. Also (usually) you have to be above a certain altitude to be able to dump fuel AND they usually do it over un-populated areas(like a very large body of water). The dumped fuel is happening over a very large area and with the airplane moving very fast through the air so it is very well spread out. The fuel molecules are too small to precipitate and cling to other things in the air, usually ending up in clouds, then rain/hail/snow/ice).

PS also not all planes are designed to simply "dump" the fuel and will have to actually fly it off.

Thanks for your input.

Silly of me to think O'Hare might have been the closest airport. From the map looks more like the TC/Petoskey area caught any fallout.

The exterior panel door issue. Dumped fuel for an hour then flew back to DTW. Maybe a couple hours before it safely landed. What about the door potentially flapping in the breeze that long?

Another question: Double redundancy. Two sensors on the panel door that set the light in the cockpit?

It could have depended on which door it was, some surface areas of the aircraft in flight have very little airflow while others have the full force of it. Also, most of he access panels have 3 or 4(maybe more) push buttons/latches to gain access. If it were just loose vs flailing about open probably not a huge "get down right now" issue.

The Pantry wrote:

Jake from State Farm wrote:

Probably around 24" plus a gravel and sand subbase. They dump the fuel so if they do have a problem landing they don't take out half the airport. Usually fuel load is calculated so there's not a whole helluva lot of fuel left when they get to the destination.

With as fucked up as most truck-trafficked Michigan roads are, you'd think some smart guy would suggest rebuilding them with a deeper base.

There's right around 3 feet of base and subbase now on interstate highways. Maybe some other smart guy could figure out how to keep them from freezing in the winter so ice doesn't blow the joints apart.