Always room to learn from others, right? Here a Boeing 787-10 comes to land with a strong crosswind. Well, first... how strong? The peak wind yesterday at LHR was, according to the METARs, 300/13G28, what gives a maximum component, in the gust, of merely 11 knots of crosswind. But, with a 15 knot possible shift in the headwind, a bit more energy during approach is desirable.
Nevertheless, with the auto-throttle ON, Boeing says no extra wind additive beyond the standard 5 knots above Vref is needed - what, of course, does not preclude us to do some last minute adjustment to our energy state.
The airplane is still well within the Autoland envelope for this condition. But here, of course, we are having a manual landing, as in the majority of the times.
Since I do not know what time was this landing, we are assuming the worst wind of the day - it was probably better than that. Take in consideration also that some optical illusions occur because of the zoom, therefore for the pilots on board, the airplane does not feel nearly as sideways as in the video.
Having said that, there are three main techniques for landing in a crosswind: sideslip, crab, and de-crab. The sideslip, for airplanes with wing mounted engines, is not a very favorable technique, because it reduces even more the ground clearance of the engine, since you would touchdown with a wing lower than the other, but curiously that's what the robots use in an Autoland, and that's why the limitation on the 787 is 25 knots.
So, the main options for human pilots are crab and de-crab. The crab is the easiest one: just keep wings level, giving enough aileron only to keep flying your main gear to the centerline. The downside of it - as we will see later - is that touching down in a crab on a dry runway not only creates big lateral loads on your wheels, but also may, in smaller models, make you veer off the runway, due to the excellent grip of airplane tires. In a heavy jet like a 787, that's not so much of an issue because the mass of the airplane is so great that the inertia itself keeps it going forward, as the video shows, with the airplane aligning itself to the centerline with little to no pilot input. Before we get back to this landing of the video and its crab landing technique, let's quickly visit the optimum option for dry runways: the de-crab.
In the de-crab you approach on a crab, but during the last 20 or 10 feet of the flare, turn it to a sideslip, ideally touching down with both main gears simultaneously, aileron into the wind and opposite rudder (cross-controls), but no roll, and the airplane axis aligned to the centerline. This works perfectly up to moderate winds, but may be combined with some crab on higher components (like 25 knots and above on a Dreamliner).
So, what was the problem with this particular landing? Why did it ended up on a balked one? Well, the key here is energy: (Continue on the comments below)
Multiple planes flying into Heathrow Airport had to abort their landing due to strong winds. British Airways Boeing 787-10 Dreamliner (G-ZBLB) aborted its landing at London (LHR) while operating flight BA156 from Kuwait City (KWI) on 26 February 2024.
#aircraft #aviation #airlines
Group VP, Middle East and Africa at BSI Freight Services
1mocongratulations on the fleet expansion, looking forward to further collaboration