FBW during the flare

[Doors to Automatic]

There have been numerous instances of aircraft going off the ends of runways in recent years and many of these were caused by the aircraft being a little fast in the flare, perhaps with a tailwind and then floating down the runway, which got me thinking......

FBW technology is now over 25 years old and in that time the sophistication of the system must surely have improved way beyond what was possible in the early days. I also noted with interest the way FBW manages the spoilers and alters the flight dynamics of the E-Jet on a recent flight I made into London City - making operation of that type possible there.

Surely by now the technology is there to use FBW to manage the spoliers and effect a miniscule deployment when the aircraft is in the flare and a float is detected, in essence to help the wheels onto the ground. If the system detects that this cannot be completed safely within a set distance it could bark "go-around", or be cancelled if TOGA application is detected.

The precise parameters would obviously have to be determined by experts but I am thinking in general terms and with reference to situations such as this one:

London Luton Airport Monarch Airbus aborted landing - Missed - YouTube

Here a go-around was initiated when the aircraft was inches above the ground and presumably caught in a tailwind and could have perhaps been avoided with a tiny deployment of the spoliers.

If this could be achieved surely there would be cost benefits (avoided GAs) as well as (hopefully) a reduction of the number of runway excursions?

Any views on whether or not this would be possible would be interesting!

[Mad (Flt) Scientist]

Defining what constitutes "float" in terms accessible to the system would be one challenge - you'd require a robust and simple means of using available aircraft data to do that. And then address various what-if scenarios based on failed or misleading data on any of those selected parameters.

You'd also have to ensure that you didn't convert a float into a hard landing, or indeed a normal landing into a hard landing. Spoiler deployment at low altitudes is recipe for trouble. So again, you'd need to have a system that didn't create new risks; which might mean limiting the authority to such an extent that it wouldn't be able to do much.

And philosophically, if we're going to say "the pilot won't land properly, let's add a gizmo to compensate" - it's simpler (and the technology does exist now) to just say "take the pilot out of the equation, engage autoland".

[Doors to Automatic]

Yes, agree that the definition would have to be pretty robust, but not so much on the "pilot can't land bit", after all modern aircraft have a range of devices which are there to help the pilot but do not mean that he/she are redundant. e.g.auto-thrust, auto-brakes, armed spoilers, TCAS and even autopilot itself to name just a few.

The new Airbuses are even equipped with a system which tells the pilot if he/she can complete the landing in the remaining runway length.

In terms of parameters, I would imagine that, put simply, the system would prevent the plane from rising or staying level once the thrust levels have been closed for say a second or longer and the altitude is below a certain level but the purpose of my question was more to explore whether such a system would be possible technologically rather than the precise parameters operationally.

[AirRabbit]

Notwithstanding all the potentials that are (or could easily be) involved with FBW airplanes … after watching the video presented here, it is apparent to me that this pilot was more interested in achieving the often highly desired “grease-job” landing than he (or she?) was interested in simply landing the airplane.

LMG touchdown at 0:17? Possibly … but not to the extent that would have compressed the strut.
RMG touchdown at 0:22? Yes.
LMG touchdown at 0:23? Yes.
Nose rise at 0:26? Yes … but only after the start of the climb.

There isn’t any information available in the following areas:

1) the airspeed that was being maintained;
2) the airspeed that would have been appropriate during the final approach;
3) the airspeed upon commencing the flare; or
4) the airspeed upon achieving the landing attitude.

Additionally, there is no information about the location about where on/over the runway that any of the above listed points were reached.

It looked to me as though there was little, if any, power reduction initiated at any point throughout the video – meaning that there was certainly some, and likely a substantial amount of excess power being carried throughout what was captured on that video. Additionally, there was an extremely slight, if any, pitch attitude change, and no observable thrust change, as the airplane began to lift away from the runway … indicating that very likely only a small amount of additional power would have been required to achieve the “go-around” shown. Not knowing any more than what was captured on that video it would make sense that in attempting to achieve that senseless “grease job” touchdowns, the pilot used up a sufficient amount of the available runway that it no longer appeared to be safe to continue with the landing.

Of course, it’s only my opinion, but that opinion is that “grease job” landings may “feel” nice, but they are senseless in that they depend on irrationally using runway length and doing so at increasingly, and unnecessarily, lower airspeeds, and in doing so, unnecessarily compromise the safety and efficiency of flying the airplane the way it was designed. Of course, there are pilots who are quite good and can achieve these “silly” grease job landings, almost whenever they choose … but that is not the way the airplane was designed, and they give the impression that being able to do that is something that all “really good” pilots should be able to do. That is, of course, patently wrong-headed, particularly when such attitudes are more pervasive when focused on younger, lesser experienced pilots, seeking to “prove” themselves!

[Tinwacker]

After watching the video and not knowing the airfield, it would appear that the pilot was too far down the runway as compared to the second landing.

I thought it was an airshow demonstrator by the first kiss and Go Around...