The crew were somewhat distracted by the fact that there was a third crewmember in the cockpit involved in training, so the pilot who was supposed to be watching the airspeeds and such, did not monitor the instruments properly, which would have alerted him to there being something wrong, and in any case with a not properly stabilised approach, this should have been a situation where he advised going around. This would not have been a problem if the crew had taken corrective actions, but since the aeroplane's systems were incorrectly indicating that it was at low altitude and about to touch down, the autothrottle closed when the aeroplane was still a couple of thousand feet above the ground. Because the crew were doing an autoland, they assumed all the automatic systems would function as they supposed, which they did not. The pilots did open the throttles up again, but if you move the throttles briefly to do this instead of holding them there, they will not stay in that position and will revert back to their autothrottle setting (in this case, idle). Things were not helped by the fact that ATC had the crew intercept the glideslope from above, which is not really what you are supposed to do, and in pulling the throttles back to try to get down onto the glideslope, the throttles automatically went into retard mode owing to the radar altimeter's erroneous information. Part of the problem was the F/O's inexperience in arming the autoland system correctly (there are a number of ways to do this, and how you do it and in what order you press the MCP buttons depends on whether it will be a single channel or dual channel automatic approach), but there was also a fault with the altimeter system and in addition to this, the pilot monitoring wasn't doing his job properly either owing to cockpit distractions. The 737 is known to be a bit 'floaty' compared to the A320 as a result of it not having as long an undercarriage as is found on the Airbus, and if you are used to flying an A320, it is as well to be aware of how this makes the 737's fairly different to the A320 in terms of landing despite the fact that they are basically rival aeroplane types.Ī good example of a real world accident where all this stuff came into play, is the heavy crash-landing of Turkish Airlines Flight 1951 at Schiphol in 2009. Surprisingly, in these circumstances, a 737 NG can be at speeds as low as around 100 knots and still not completely quit flying owing to that air cushion effect, so you need to be aware of this. Since this is not always the case, it's fairly common to do an automatic ILS approach initially, then disengage everything and finish the landing manually, and to do that, basically you want to be switching everything automatic off as you come over the runway threshold, closing the throttle manually and using the flare to bleed off speed so you touchdown smoothly.Īt light weights, a 737 will float quite a bit and since it will be in ground effect at low altitude (the air being forced down under the wing bounces off the ground and provides a cushion which the aeroplane rides on). However, various types of autoland categories require certain parameters to be met (runway visual range, MDA, that sort of stuff) and the crew have to be qualified and current on the approach/autoland type. the pilot monitoring) to observe the speeds and stuff to make sure everything is cool. As the aeroplane flares, the speed bleeds off and theoretically you come in and touchdown at the correct speed, but it is still the job of the co-pilot (i.e. On a 737 NG, the autothrottle takes data from the radar altimeter and closes the throttle automatically at a suitable altitude (27 feet AGL), which is why it is fairly important to have the Vref speed set up correctly for the weight.
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