About how fast is a passenger aircraft (assume a 747 or MD-80 or similar “workhorse” craft for this discussion) moving when its wheels touch the ground? After the pilot hits the brakes, about how fast will it be moving when the pilot can safely execute a turn to get it off the runway and towards the gate? And about how much distance transpires between “wheels hit the ground” and “the plane is no longer on the runway”?
That’s for Boeing planes landing speeds. Not sure about the other questions.
Pretty fast for a 747. Their landing speed is about 150 knots (approx. 170 mph). That is air speed however and airplanes generally land into the wind so you also have to subtract off the headwind. Still really fast though.
FWIW the Concorde was even faster, 185 MPH landing speed and 250 MPH takeoff*!* It’s high takeoff speed contributed much to it’s fatal crash (and several other tire blow-out incidents it suffered over the years).
Landing distance for a 747 depends on a lot of factors including weight, air density, wind speed and how aggressive the pilot needs to be. However, they generally need a minimum runway length of well over a mile and runways shorter than 6,000 feet require special planning and are rarely attempted at all let alone with passengers or significant payload. That is with ideal (dry) conditions at sea level. The shortest official landing for a 747 was during a test flight using a highly skilled pilot and stripped down plane under ideal conditions. He managed to get it stopped in 4,200 feet using the slowest approach possible and every available emergency braking and control system but that is far from normal and a 747 loaded with passengers wouldn’t be able to stop that quickly no matter how hard the pilot tried.
The typical 747 runway is over 2 miles long so the pilots don’t have to use excessive braking procedures which are hard on both the plane and passengers. 11,000 - 12,000 feet of runway may sound like a lot but it gets used really quickly when you touch down at about 170 mph.
How quickly the pilot turns off the runway is controlled more by ATC and the airport design combined with the desire to maintain passenger comfort than the capabilities of the aircraft. I am not sure what the maximum speed is for a 747 to make a tight turn but I do know pilots generally avoid turns so tight that they stress the capabilities of the aircraft because they aren’t safe or comfortable.
I don’t know how common it was, but Boeing used to fly 747s to Renton airport on occasion, and that runway is only 5,382 feet. Someone told me that early in production Boeing didn’t have a paint facility at Everett and had to fly the unpainted planes to Renton.[sup]*[/sup] Whatever the reason, there’s video of a 747 landing a little too short and tearing off one of the landing gear, so it sounds like they were trying to land as close to the threshold as possible.
- Boeing built, and still builds, their narrow-body airliners at Renton (with at least one exception) . For the 747 project they built a new assembly facility at Everett, and all the ensuing wide-bodies have been built there.
Another factor to consider is that all approach speeds quoted for airplanes are given in indicated airspeed, not true airspeed.
At sea level, these are equivalent, but at higher altitudes, indicated airspeed is lower than true airspeed because the air is less dense. The “indicated” airspeed represents the aerodynamic forces the plane “feels”, and all flight maneuvers (including landings) are conducted with respect to indicated airspeeds.
At sea level, a Boeing 747 will land at an indicated airspeed of 150 knots (173 mph), which will also be the true airspeed.
But on a hot summer day in Denver, the indicated airspeed will still be 150 knots, but the plane will actually be moving at a true airspeed of approximately 170 knots (~195 mph).
All Boeing single aisle airplanes are built in Renton. The only exception was the 717, which is just a renamed MD95. As a long time Boeing employee, we don’t consider it to be truly a Boeing product. Boeing also builds wide bodies in Charleston, South Carolina too.
I also watched a 747 take off from Renton. It actually lifted off a couple hundred yards from the end of the runway. The option of not taking off in time was a dip in Lake Washington.
I was thinking of the 717 when I wrote that. I knew it was a re-badged DC-9 variant, and one source said it was the last plane built at the Long Beach factory. I also saw reference to a proposal to start a 737 assembly line there, but it sounds like it never got beyond the idea stage. Add in the military variants, like the original 717, and I figured I better leave myself some wiggle room.
Boeing always used to threaten to move production to someplace like South Carolina whenever there was the prospect of a machinists strike, but I didn’t know they’d gone as far as starting up another facility.
I heard someone several years ago (and it may have been here) say that Boeing used to be an engineering-centered company; they built the best planes because they listened to, and promoted, the people who designed and built them. But now they’re just in the subcontracting business; they move pieces around the globe based on politics, unions, and tax breaks. If that’s true it’s a damn shame.
Would have liked to have seen that. I took my first flying lessons, and had my first solo, at Renton. I’m sure they took off with enough fuel to make Boeing Field, which would take about five minutes, and not a whole lot more. And I hope the wind was from the north.
Those numbers would be for max landing weight. I don’t fly a B747 but I can’t imagine a long haul aircraft would be at max landing weight very often.
Also the speed across the threshold would normally be 5 knots slower than the final approach speed and the touch down speed is slower still.
In the RJ100 I flew the approach speed at max landing weight is 124 knots, threshold speed would be 119 knots and touchdown speed (ideally) should be 112 knots. If a B747 is approaching at 157 knots you can expect the touchdown speed to be at least 10 knots slower.
For a turn, I’d think about 15 knots or less for a 90º turn, any faster feels uncomfortable. High speed exits can be taken at 55 knots though. They are taxiways that peel off the runway at an angle allowing you to get off the runway more quickly.
Just thought of something else. The actual ground roll from touch down to turning off the runway is significantly less than the runway distance required for landing. For starters you normally touchdown about 1000’ into the runway, so if you’re landing on a 5400’ runway, you’re really only using ~4400’ of it.
I recall landing at an airport in Brazil. Watching the high rise buildings zoom by at our level.
The instant all wheels were on, we were all flung forward by the hard braking and reverse thrust. Never had such a fast deceleration, and have been to some interesting strips. Then we did a hard turn at a very high rate of speed.
Wondered what the hell was going on.
As we turned, I saw the end of the runway. Which in spite of the hard deceleration, we were close to.
Yellow and black stripes painted on a tall concrete wall. Yikes.
Sounds like you landed in Congonhas airport in São Paulo. It’s an over used, small airport (build in the 50s I think) and it’s located today in the middle of a sea of high rises…
According to the little flight-map/data screen on the seat back, it has been in the 150-180mph range on flights that I’ve been on. No doubt it varies pretty much through that range depending on the type of aircraft. Seems like I’ve been flying Airbus 330s a lot lately.
That is the one. But after I posted, I looked up pictures. None seemed to show a wall at the end of a runway. But they were aerial shots. It was the most extreme fair weather landing I ever had in a big passenger jet. Had a few exciting ones in bad weather. And isolated strips. I read that it has been downgraded and the bigger equipment uses the other airport now. Strange that I flew in there from Toronto, then crossed town to get a local flight out of the newer airport.
I was quite impressed and pleased that they had the statistics from the DC-3 and DC-4 listed in that table.
I wonder how many of those old workhorses are still in commercial use.
The DC-3 is probably my favorite airliner overall. There are no exact counts of the number still in regular use because they tend to be located in remote parts of the world these days but the best estimates are still in the hundreds which is remarkable for 1930’s technology. They are still very much serviceable workhorses and not museum pieces. Few other current aircraft can fulfill their mission especially for the price.