曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
gripping the reverse thrust lever (RTL) before shifting it. A situation is possible
where the rear part of the palm of a pilot's right hand touches or leans on the
knob of the TCL of the left engine after shifting the RTL to MaxRev.
This creates a form of "semi-rigid connection" between the RTL of the
right engine and the TCL of the left engine, which functions only in one
direction while shifting the RTL forward, that is, when deactivating the reverser.
The nature of shifting the TCL, depending on the position of the RTL of the
right engine, practically fully coincides with the data from recordings of the
FDR during the accident flight.
In conducting the experiment to confirm this version, this connection was
artificially created using Scotch tape with different degrees of elasticity. A very
"hard" or very "soft" connection did not lead to a precise repetition of the results
recorded on the FDR. A medium degree of tape elasticity quite accurately
recreated the scenario of shifting the TCL when shifting the RTL. This attests to
the fact that the fingers of a pilot's hand did not grasp the knob of the TCL of the
left engine and that the palm while resting on the knob was slightly sliding as
the RTL was moving forward.
The best congruence of the experiments with FDR recordings of accidental
flight was achieved on aircraft with low friction forces in the TCL cable (0.4 -
0.6 kg). This is indirect evidence of the possible existence of small forces when
shifting the TCL on the F-OGYP airplane.
Before 22:44:16 the airplane captain, to all appearances, continued to rest
his right hand on the TCL of the left engine (this could explain the minor
shifting of the TCL backward (22:44:02 – 22:44:16), after which the airplane
captain transferred his right hand to the control wheel in his attempt to help
maintain the direction of roll by means of the bank displacement of the control
wheel.
5 All findings and conclusions made in this chapter are the opinions of the person who performed this assessment
and may differ from the findings and conclusion of the whole report.
Final Report
INTERGOVERNMENTAL AVIATION COMMITTEE
68
A repeated attempt to activate the reverser on the airplane captain's
command "reverser once again" (22:44:20) was executed by the co-pilot since
the execution of this action by the airplane captain would have led inevitably to
the shifting of the TCL of the left engine, which was not confirmed by FDR
recordings.
2 Effect of friction forces in the control cable
Measurements of friction forces made on the Uzbek airplane showed that
their magnitude depended on the "flight hours" of the airplane and was lower
than the standard (1.17 - 1.54 kg) in all cases.
The А-310 F-OGYP airplane that was involved in the accident on July 9,
2006 was manufactured in 1987 and had flying hours of more than 59,000
hours, that is, one can assume with a high degree of probability that the forces
for shifting the RTL were lower than standard.
The experiments conducted on airplane with various forces (from 0.4 kg to
2.1 kg, see table below) showed that in a specific position of the hand whose
rear part of the palm is resting on the TCL knob of an engine with a deactivated
reverser the unintentional shifting of the RTL forward is possible when
deactivating the reverser on the other engine and when the pilot (pilots) does
(do) not have visual control.
In addition, the lower the forces the higher the possibility of imperceptible
shifting. So with forces of less than 0.6 kg the position of the TCL almost
corresponds to the positions recorded by the FDR on the accident flight. With
intermediate forces (0.8 - 1.0 kg) the pilot begins to feel resistance when shifting
the TCL and the magnitude of its deviation on all segments is approximately
20% less in comparison to the small forces of friction.
Under the specified forces (1.17 - 1.54 kg) the resistance to shifting
becomes noticeable and the displacement angle of the TCL on the dial is
reduced by 40% - 50% compared to the small forces.
Table 1. Positions of the TCL of the left engine when deactivating the reverser
on the right engine on fixed fields in case of different forces of friction when
steering (on the TCL dial)
№ of field Emergency
flight
Friction
forces
0.4 - 0.6 (kg)
Friction
forces
0.8 - 1.0 (kg)
Friction
forces
1.2 - 1.5 (kg)
Friction
forces
2.0 - 2.1 (kg)
1 6º 5º-7º 3-5º 2º-3º 2º-3º
2 16º 14º-17º 12-13º 10º-12º 8º-10º
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FINAL REPORT ON THE RESULTS OF THE INVESTIGATION OF THE ACCI(34)
