Can the Airbus A380 or Boeing 787 land safely without flaps/slats/spoilers or thrust reversers?
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asked May 23, 2014 at 18:52
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5$\begingroup$ yeah they will come in overspeed and need a long runway to get to a stop $\endgroup$– ratchet freakCommented May 23, 2014 at 18:54
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20$\begingroup$ For what it's worth, the Boeing 787 is not a "super." Its MTOW is less than even a 777 (all variants), let alone a 747. The 747 is still Boeing's heaviest aircraft. (A modified 747 was even used to carry 787 pieces, like its wings, around.) $\endgroup$– TypeIACommented May 23, 2014 at 20:13
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2$\begingroup$ @Federico, at taxi speeds a heavy plane like a 747 at Max Gross has a limit as to how far it can taxi before the tires overheat. It is not just the brakes! So I am wondering if a landing with slow braking will overheat the tires not the brakes. I don't know the answer. $\endgroup$– Skip MillerCommented May 23, 2014 at 22:11
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3$\begingroup$ @SkipMiller, if you're landing with no flaps, then you have a LOT of energy to get rid of, and unless you have enough runway that the thrust reversers can get rid of most of it, then quite a bit of energy IS going into the brakes. So they're going to be hot. That's just what's going to happen with most no-flap landings. Braking "slowly" won't help much -- you have some amount of kinetic energy that needs to be absorbed by the brakes, so whether it's absorbed over 10 seconds or 30 seconds, it's all going into the brakes. If you have to land no-flap, then hot brakes is probably a given. $\endgroup$– Ralph J ♦Commented Mar 16, 2015 at 15:20
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3$\begingroup$ But then you have also more time to dissipate that energy $\endgroup$– AntziCommented Dec 22, 2015 at 19:03
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3 Answers
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Even the largest commercial airliners are able to land without flaps, since flap failures do happen occasionally. See a report here where an A380 landed with no flaps. This was at the Auckland, New Zealand airport, where the runway is 3,635 m (11,926 ft) long.
The pilots have checklists to follow in the event of issues with flaps, which include information about what speeds they should fly with what amounts of flaps. They simply land at a higher than normal speed. The brakes can end up getting hotter than normal, so they may have to stop and let them cool or have them inspected by emergency services. The tires are designed to deflate with fusible plugs before high temperatures would cause them to blow.
Aircraft are also tested to make sure they can reject a takeoff at high weights (higher than normal landing weights) using no thrust reversers. Here is a video of the 747-8 doing this test.
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2$\begingroup$ I've never heard about the designed-in tire deflation, is there an article I can read? $\endgroup$ Commented May 23, 2014 at 19:52
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1$\begingroup$ @CGCampbell Check this video out youtube.com/watch?v=qc_v6tXsv6g (same as posted above). At the end of the test they mention and show the deflation of the tires due to heat. $\endgroup$– zundiCommented May 23, 2014 at 20:55
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1$\begingroup$ PBS had a multivolume video series (4 or 5 tapes) on the design, construction, and testing of the 777. The torture tests of brake overheating caused the fusible plugs to blow, so that fire crews wouldn't be endangered by exploding tires. $\endgroup$ Commented May 23, 2014 at 22:34
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9$\begingroup$ @PhilPerry Unlike the A340-600 RTO test, where the tires did explode. Some selected quotes:
"It's not an important fire.""Bring the stairs.""Bring the stairs, now!"$\endgroup$– reirabCommented Jul 27, 2015 at 20:33 -
1$\begingroup$ @CGCampbell, see also: What's the difference between tire deflation & explosion $\endgroup$– FreeManCommented Dec 23, 2015 at 14:10
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Specific information can be difficult to come by, and each airline may have their own guidance on the subject. I wasn't able to find anything for the 787, but for the according to one 777 crew handbook I found, flaps up landing was not part of certification:
All Flaps and Slats Up Landing
The probability of both leading and trailing edge devices failing to extend is extremely remote. System reliability and design have reduced the need for some traditional non-normal landing procedures. As a result, an all flaps up landing NNC was not required for airplane certification and does not appear in the AFM or in the QRH.
Basically this means that a demonstration of a no-flaps landing was not required during certification, so no specific guidance appears in the official handbook, and the manufacturer makes no claim that it can be done safely.
None of the Boeing 787 handbooks I found had official procedures for a flaps-up landing either.
That doesn't mean that it can't be done, but pilots are "on their own" so to speak, and the airplane may not be usable afterward.[*]
But the basic procedure you'd expect them to follow is somewhere along these lines:
- Attempt to troubleshoot flaps first (best to avoid the problem altogether)
- Remove excess fuel (either dump or burn)
- Pick suitable airport considering runway length, altitude, and safety gear (e.g. EMAS)
- Declare emergency and prepare airport (ready the fire trucks, etc)
- Approach above no-flaps stall speed and touchdown as close to the start of the runway as possible
- Engage brakes, spoilers, and thrust-reversers as appropriate
- "Please please please stop..."
- Write a book.
[*] "If you can walk away from a landing, it's a good landing. If you use the airplane the next day, it's an outstanding landing."
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2$\begingroup$ A minor nitpick: Remove the excess fuel (either dump or burn) after picking a suitable airport ;) $\endgroup$– dooburtCommented May 25, 2014 at 10:48
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2$\begingroup$ @dooburt as long as you're nitpicking, declare an emergency first, otherwise you've got to follow your original fight plan. The order isn't strict. $\endgroup$– tylerlCommented May 25, 2014 at 15:03
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1$\begingroup$ that was a given - hence the ;) on the end. Written in humour. A comprehensive list nonetheless. +1. $\endgroup$– dooburtCommented Jun 4, 2014 at 8:37
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Any aircraft can land without those devices. I would say that the Gimli Glider is a nice example, with no power it could not extend its flaps/slats.
They are used, as @ratchetfreak notes in the comments, to reduce the touchdown speed and, as a consequence, the runway length needed to reach a stop or taxiing velocity.
To be noted, also, that a safe landing is mostly defined by the vertical velocity at tochdown, usually in the order of 1-3 feet per second. See for example this accident report where it states
mild touchdown rates [...] less than 5 feet per second
Since the vertical component is the relevant parameter for a safe landing, and given that without flaps/slats the forward velocity will be larger than usual, the aircraft will have to approach with a shallower angle than the usual 3°.
The absence of thrust reversers, as you might imagine, will only affect the braking process.
answered May 23, 2014 at 19:19
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$\begingroup$ The Shuttle Landing Facility's 15,000 foot runway isn't always available... any info on the A380's landing distance without flaps/slats/reversers? Is it indeed feasible on "normal" runways at large airports? $\endgroup$– TypeIACommented May 23, 2014 at 19:40
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3$\begingroup$ Didn't the Gimli Glider get stopped by having its nose gear collapse? $\endgroup$– TypeIACommented May 23, 2014 at 20:10
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1$\begingroup$ @dvnrrs yes, but the touchdown went fine $\endgroup$– FedericoCommented May 23, 2014 at 20:24
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1$\begingroup$ @dvnrrs - the landing gear didn't collapse, it was never locked down properly in the first place $\endgroup$ Commented Dec 23, 2015 at 12:59
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1$\begingroup$ Another example (also a deadstick landing) is Air Transat flt 236, an A332 that landed with no flaps, no spoilers, and no reverse thrust, only slats and braking. They landed fast, braked hard, deflated most of the tires and stopped using most of the 11,000 ft runway. However their vertical speed on touchdown was high enough to cause the aircraft to bounce $\endgroup$ Commented Sep 26, 2016 at 19:11