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
the neutral position when not being moved by a pilot.
When a pilot operates the relevant side stick, the movement of that side stick
provides an electronic demand ‘order’ to the aircraft’s flight control computers. The
flight control computers respond by providing the necessary outputs to the relevant
flight control surfaces to achieve the desired states of pitch and/or roll. When the
second pilot simultaneously operates the other side stick in the same or opposite
direction, the demand ‘orders’ from both side sticks are algebraically-summed as a
‘global’ electronic demand ‘order’ to the flight control computers. The total ‘global’
– 16 –
demand ‘order’ is limited to the maximum deflection demand ‘order’ able to be
provided by the movement of a single side stick controller.
On the A340, one pilot is able to deactivate the other pilot’s side stick controller to
take full lateral and longitudinal control of the aircraft. That is accomplished by the
pilot activating the side stick priority button on the relevant side stick controller. The
operator’s FCOM contained information that, if a take-over became necessary during
flight, the pilot not flying (PNF) was to clearly call ‘I have control’, and to press the
side stick priority pushbutton, keeping it pressed until the transfer of control was
clearly established.
Side stick operation – dual inputs
The operator’s A340 FCOM also contained information that the PNF should not
make control inputs to correct the handling of the aircraft by the PF. The lack of a
direct mechanical linkage between the side stick controllers meant that there was no
tactile feedback provided to the PF if the PNF was making concurrent or dual side
stick inputs.17
The aircraft was, however, fitted with a warning system to alert the crew of
simultaneous inputs on both side sticks in the event that the side stick priority system
was not activated. A 2-degree deflection of the PNF’s side stick in any direction from
the neutral position resulted in the illumination of the green SIDE STICK PRIORITY
warning lights on the glareshield in front of each crew member. In addition, the
‘DUAL INPUT’ synthetic voice message was activated by the flight warning system.
The aircraft manufacturer has examined the reasons for dual sidestick inputs during
line operations. Advice received from the manufacturer included that, in normal
flight conditions, the practice should not occur if ‘…proper airmanship and CRM
[crew resource management] applied.’18
An analysis by the manufacturer of reported instances of dual sidestick inputs has
revealed they may be ‘spurious’, ‘comfort’, or ‘instinctive’ interventions on the part
of the PNF. Those inputs can be defined as follows:
• Spurious dual inputs. Spurious dual inputs are unintentional, are of short-term
duration and small in magnitude, and result in only marginal effects on an
aircraft’s pitch and roll.
• Comfort dual inputs. Comfort dual inputs are intentional, short-term
interventions by the PNF. The intention of the PNF is to correct or improve the
aircraft’s attitude or trajectory during a precision manoeuvre, such as a landing
approach or landing flare. Comfort inputs are normally small deflections, and
may be the same as, or opposite to the PF’s sidestick inputs. They usually result
in only minor effects on an aircraft’s altitude and/or trajectory, and are ‘…thus in
most cases unnecessary.’ In most cases, the PF was unaware of any ‘comfort’
inputs by the PNF.
• Instinctive dual inputs. Instinctive dual inputs are ‘reflex’ interventions by the
PNF, acting out of surprise at some unexpected event that may occur during a
17 The aircraft manufacturer indicated that the interconnection of the aircraft’s side sticks
‘would be operationally not beneficial and technically not efficient’.
18 Airbus ‘Operational Liaison Meeting A320 family, A330, A340’ - 2002.
– 17 –
dynamic flight manoeuvre, such as the landing flare. Those interventions are
significant in terms of stick deflection, and are usually initially in the same
direction as the PF’s stick inputs. They have the potential to affect an aircraft’s
behaviour, and may lead to over-control of an aircraft. As with comfort dual
inputs, in most cases the PF is unaware of any ‘instinctive’ dual inputs by the
PNF.
Previous incidents involving dual sidestick inputs on ‘fly-by-wire’ aircraft
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：
航空资料2(164)
