I don’t know. But I was told by the airport manage in Rock Springs, Wyoming that a 707 made an emergency landing there a long time ago. The runway there was at that time about 8000 ft long and the airport altitude is 7500 ft.
They emptied fuel until they had enough to get to Salt Lake City plus some; took out all the seats and, of course had no baggage; waited for a clear day with a wind directly down the runway and were cleared into Salt Lake City on an emergency basis so they had priority; and took off running the engines to takeoff power with brakes on, releasing and using a lot of flaps.
Many years ago a (Southwest, I think) commercial jet enroute to Corpus Christi accidentally landed at the old WWII NAS strip - barely. As I recall, they had to partially disassemble it and truck it out.
Provided there is sufficient runway for takeoff just like they would from any other airport. Takeoff distance can be shortened by getting the gross weight as low as possible and by taking off when temperature is coldest. All passengers would of course be off and they’d probably remove all cargo containers and possibly defuel until they had just enough for a safe flight to the nearest large airport of facility. Cold air means higher density which means more lift for a given airspeed.
If the runway is long enough that they can physically launch the airplane they will do so - but as already mentioned, they may have to do this will minimal fuel, unload baggage, seats, or other items, and arrange other things so as to do this safely. It’s actually quite remarkable just how little runway a big airplane needs to get off the ground. Of course, the closer you come to the very edge of the performance envelope the less your margin for error - this would NOT be done with passengers on board, only the very minimum number of people required for the flight.
If the runway isn’t long enough (and you can land on a shorter runway than you can take off from) then the only alternative is to disassemble the plane and truck it out to an airport suitable for take-off.
In real life, there have been big jets that ran out of fuel and make successful emergency landings, the best known being the “Gimli Glider”, a Air Canada plane. Google on that and you’ll get an interesting story.
I had the Gimli glider in mind. An amazing story considering the type of runway it used (ie. a go-kart track with a large concrete median down the centre of what used to be the runway). It was discussed here on these boards a while back, and it interested me, so I googled lots of stuff about it, but I don’t remember reading what they actually did with the aircraft (from memory, I’m picturing it in a nose-down attitude with the landing gear totalled, and considerable fuselage damage, but in pretty much one piece). I’m assuming it was taken apart and trucked out of there.
The Gimli glider was flown out about a month later. Interesting side note, a van full of Air Canada mechanics on their way to Gimli had their van run out of fuel on the way. DOH!
I beleive that the median was an Armco (metal barrier) IIRC. Also don’t forget that Gimli was an old AF training base, so the runways were long enough for a big plane.
One thing that has not been mentioned in this thread is the strudiness of the runway. I recall a newpaper article a number of years ago about an airline pilot that screwed up his approach to Burbank. He lined up with a runway and called the tower that he was on final. Unfortunally he was line up on Whiteman Airpark, a small general avaition field that at the time was uncontrolled. A very alert controller at Burbank realised that he did not have this 737 in sight. He told the pilot to abort and they got the mess straightened out befre the wheels touched the ground. I seem to recall that the plane got as low as 500 feet before starting to climb again. The newpaper article about this story mentioned that had the plane touched down that it would have broken through the runway as it was not designed to hold such weight.
No information on how they removed either of those aircraft. It’s just good to know the planes are somewhat more aerodynamic without power than a hunk of metal (as I’d long suspected they’d behave).
Can’t remember where I read this or about what plane, but the phrase that stuck in my mind was someone describing a particular kind of plane, should the engines quit having “the glide characteristics of a brick.”
Apparently, the commercial jets are a bit better than that these days.
It all depends upon the wing loading. For example, the WWII Martin B-26 had a wing loading at max gross takeoff weight of about 40 lb/ft[sup]2[/sup] which was considered high at that time. Now it would be low.
According to this site the Boeing 747-300 can weigh as much as 833000 lb. at takeoff. The wing area is 5500 ft[sup]2[/sup] which gives a wing loading of just over 151 lb/ft[sup]2[/sup]. However, that is in the in-flight configuration of the wing. The 747 and all such planes really put on a different wing for takeoff, landing and other low airspeed operation. The wing area and aerodynamic properties, such as aspect ratio, camber etc. are entirely different for the landing configuration than for the cruise case and I couldn’t find any data for that.
Incidently, the B-26 also had a different wing for landing and takeoff than for cruise. It had Fowler flaps which move back as well as down and increase the wing area and provide slots in the wing to help prevent flow separtion and consequent poor performance.
Hometownboy - The F4 Phantom used to be described as having the glide characteristics of a brick or a rock. It had some unusual (for those days) control surfaces, too. Slots, stabilators, and BLC come to mind…
Padeye - Howdy! I haven’t been on the boards for a while because of my new work assignment. Good to see ya again.
For an education on modern aircreaft wings, sit back in the cabin and watch the wing at work turing takeoff and landing. Especially landing. The leading and trailing edge flaps go out and down. Little rectangular spoilers pop up and down from time to time. The thing is a sophisticated aerodynamic machine that changes shape before your very eyes.
The first time I sat behind the wing on a 747 when we landed it looked like the wing had exploded. Huge, flat spoilers on the trailing edge suddenly extended up almost immediately on touchdown. These add a lot of drag and kill lift which increases traction and braking effectiveness.
Without such wings a flight speed regime from takeoff speeds like 150 kts. up to mach 0.8 and higher just wouldn’t be possible.
BLC stands for Boundary Layer Control; which consists on blowing air over the wing (usually bled form the engines) to keep the boundary layer (the layer of air that´s closer to the wing) from separating and causing more drag and eventually stalling the wing.
The Ohio State University airport in Columbus once had an unscheduled visit by a TWA 707 whose crew hadn’t checked their charts. It was successfully flown out after lightening the load, but not until enough photos had been taken to line the walls of the airport cafe, which was renamed the 707 Lounge.
I’ve been told of a similar incident involving a Northwest 727 and a small field under the eastern approach to Portland, OR. The story was that it had to have the wings and tail removed and several flatbed trucks brought in.
I wonder if a 747 can be disassembled and then made airworthy again after reassembly. I’m not sure that longitudinal sections of the fuselage come apart. Even if they do, the thing is, what, 20 ft. wide? Maybe if one of them managed to get stopped on a runway that is too short for takeoff, even when as light as possible, it would be cheaper to buy the land and extend the runway, or just make a museum out of it.
Legend has it (it happened before I was there, so I can’t verify) that a 707 had to make an emergency landing at the old Columbia, Missouri municipal airport – which was not equipped for jets. They got it back up in the air after they had unloaded almost everything off it, everything David Simmons talked about in his earlier post.
But perhaps the pilots on the board can enlighten me further. Isn’t the real issue with a large jet the ability to LAND safely in a short distance with a heavy load, not the ability to take off with a light load?
This is what flight simulator is for! According to that program, a 747 can take off from a runway of about 3500’ with a few mph headwind and 20% fuel. That’s surprisingly little. I am pretty sure kunilou is right in that a plane can probably take off from an airport if it landed there in the first place. If they take it apart to get the plane out of there it would probably be for safety reasons. I can’t find actual 747 landing/takeoff distances on google… That’s surprsing. Can anyone find those?