Rechts ziet u een recente analyse van de media op basis van coördinaten. Links boven in rood de vlieghoogte van de A320 tussen 10.00h (vertrek) en 10.41h (crash). De zwarte lijn is de snelheid. Anders dan bij een auto wordt de snelheid niet gemeten op basis van draaisnelheid van de wielen, maar met coördinaten over land, omdat een vliegtuig nu eenmaal vliegt. Om een eerste gevoel te geven van verhoudingen, bij een snelheid van 740km/uur, legt men 12km per minuut af. De afstand van de rode lijn is ongeveer 10km.
Het vliegtuig zet om 10.33h een daling in. De laatste minuut (10.41) gebeurt er weer iets vreemds. De snelheid neemt toe en het vliegtuig duwt de neus weer ophoog. Dat kan zijn, omdat iemand op het allerlaatste moment een tevergeefse poging doet om het vliegtuig te redden en de berg te ontwijken (maar waarom neemt dan de snelheid toe?). Een andere verklaring is, dat er in die laatste minuut een zwaar gewicht verwijderd is uit het voorste deel van het vliegtuig (10.40h). Dit is wat er gebeurt als de piloot van het vliegtuig vlucht met een ejection cabin (een zeer dure schietstoel cq. parachute). Ik vermoed dat laatste.
A review of the Cockpit Voice Recording (link)
At 10.10h the pilot Sonderheimer tells Lubitz, how later on he needs to go to the bathroom (it is expected he will do so at cruising altitude). At 10.27h, the plane has reached cruising altitude. The captain Sonderheimer suggests to co-pilot Lubitz, he should prepare the automatic pilot for landing already. As this is too early in the flight schedule (they are expected to land an hour later!), Lubitz does not respond immediately, but suggests to wait and see. Lubitz confirms to the captain he can go to the bathroom now, if he wants to.
A door is heard. Reprogramming of the automatic pilot is heard. Next, only Lubitz breathing is heard. He remains in his chair. Based on the Voice Recording one would think Sonderheimer left the Cockpit. [please, read my alternative theory] At 10.32h the landing begins. The speed is reasonable steady, but the flying height decreases 1km per minute. At 10.33h Sonderheimer is heard for the first time knocking the cockpit door: “It’s me!”. He should already know something is not right, as the angle of flying is a fast (yet controlled) descent. In terms of flying conditions, nothing really changes untill 10.35h. Same speed. Descent of 1km/minute. [please, read my alternative theory]
If Lubitz crashed the plane, why would he use the autopilot? My answer? It is captain Sonderheimer who needs to crash the plane by autopilot, as he plans to leave the plane himself by ejection cabin. At 10.36h or so, the flying speed decreases. It is unknown why. On the Cockpit Voice Recording no reprogramming noises were noticed at the first Black Box analysis. It is likely the captain had this planned in, when he programmed the descent (10.27h). It is the only thing that makes sense. A lower speed increases the chance of survival in an ejection cabin. [Andreas Lubitz on the other hand, when guilty, would have no reason to a) crash using autopilot, b) take 11 minutes to do so, and c) reduce speed.] He started lowering speed once he was on the other side of the cockpit door. If he had decreased the speed beforehand, people might have started “wondering what is going on” before he was on the other side of the door.
At 10.40h, a violent sound can be heard outside, while the plane shakes once. At the same time, inside, screaming. The Airbus then hits something with its right wing. In my alternative theory, the captain Sonderheimer (likely with one accomplish) leaves the plane that very moment, using a most expensive parachute: an ejection cabin. This explains what happens at 10.40h. (link) A sudden shake/turbulence of the plane, a voilent noise outside, and the cargo door hits the right wing.
At 10.41h the airplane hits the Estrop mountain range at 1500 meters. Just before that happens, in that last minute, both the speed and the altitude change. It seems the aircraft’s speed is at its lowest at 10.40h (about 700km/h) and then immediately increases. The altitude (descent angle) changes as well, as if someone is trying to pull the airplane’s nose up again (no further descent). One explanation for this would be, that someone onboard notices the cockpit doorpanel open and he/she now tries to stop the descent in a last attempt to save everyone. But this should have been heard on the Voice Recording.
A likelier explanation is that the flight path is impacted by the ejection cabin. The ejection cabin is catapulted up with force, followed by a rocketering mechanism that “shoots” it far away (after which a parachute opens). This is what happens at 10.40h. Beware, a two persons ejection cabin, might weigh as much as 800 kilo or even more (an estimate, we do not know the design). After the (short) effect of the rocketering mechanism pushing the plane down, which results in one heavy shake (10.40h), the loss of this weight in the front of the plane, could be the cause of the increase in speed as well as a shift in balance/directionality (nose upwards due to weight loss in front).
I would welcome an aviation expert to help me out here. Dear readers, I promise to detail my calculations later on when I have time to study it (this is based on only basic Physics knowledge). From what I could find, an A320 airbus (empty) weighs 42,400kg and is 36.6 metres long. The maximum weight for take-off (incl. fuel and luggage) is about 76,000kg. The maximum weight for landing (incl. some fuel left and all luggage) is 65,000kg. I further assume they have limited the fuel onboard, to reduce the risk of an explosion while the ejection cabin rocketering mechanism ignites. Since the A320 has a central fuel tank, two inner wingtanks and two outer wingtanks (a unique feature), it is possible to let go off the fuel in the central tank and two inner tanks, while there is still enough left in the outertanks (tip of the wings). We have reason to think they let go off fuel, as there was no large fire when the plane crashed. In that case, the fuel weight (in the middle of the plane) is also limited. Let us assume the aircraft weighs 60,000kg incl. ejection cabin and all.
A loss of about 800kg in the front positioned at the cargo door, will impact the descent angle (due to balance) and speed (due to F=m x a). Add to this b) the weight loss of some fuel (unknown weight, positioned central in the aircraft, likely gone before 10.38h); c) the weight of the captain and likely a second accomplish (estimated 90kg and 80kg, positioned in the front, e.g. the cockpit and front isle); and d) the weigh of the lost door (estimated 30kg). With the data I have, I can not determine how much exactly this weight loss will “push the nose up” or increase speed. My estimate based on the graph above is that the decrease of speed was about 4% per minute between 10.35h and 10.40h, after which the speed increases with about 2% per minute (based on the graph above).
This +2% [a, is versnelling] is in line with the increase of speed per minute expected when a 60,000kg body [m, massa] loses about 1,000kg while in movement. The loss of weight increases speed significantly (F= m x a). Force F is constant initially, as the autopilot will take time to respond to new circumstances. (Also, opening the cargo door itself, might limit steering options in the cockpit, in case anyone would make a last attempt to save the plane: link)
It also impacts the directionality of the plane upwards towards an almost horizontal flight in the last seconds, according to the graph above. This increases speed even more, as speed is measured by land coordinates (impact only +0,3% or so). Some time later (10.41h), the autopilot should compensate for these changes (autopilots need a few seconds to respond), unless of course the cargo door interferes with autopilot mechanics. But we don’t have any data after that. The plane crashes seconds later.
ps. The conclusions are solely based on my general knowledge of Physics, of which I am by no means an expert. If I would have had more rough data about this particular flight, aerodynamics in general, and the response time of an airplane on autopilot, I would be more certain. However, while the formal media story is not supported by the flight data of the last few minutes on this tragic flight, for now, my alternative theory of an ejection cabin seems a reasonable explanation for what happened the last few minutes.