空客A320系列飞机低速中断起飞的理论和风险控制
2013-08-18 11:40阅读：
中断起飞是飞行中易引发事故的一种特殊情况。对中断起飞和继续起飞进行全面透彻的分析对于保证飞行安全，提高飞行员的专业素养有着重要的意义。然而低速中断起飞发生的机率要高于高速中断起飞，本文以A320机型为例对低速中断起飞（速度100节以下）的相关理论进行研究，分析低速中断起飞存在的风险，并提出相应的风险控制操作建议。
一、中断起飞的相关定义
FCOM有以下内容：
中断起飞的决定和停机动作应由机长进行。
因此，机长不管是PF还是PNF，应将手扶在推力杆上直到V1。一旦他决定中断，则喊出“中断”，接替操作并完成停机动作。
不可能列出所有导致决定中断起飞的因素。但为了帮助机长决断，ECAM抑制了那些从80kt到1500英尺(或离地后2分钟，以先达到的为准)中不重要的警告。根据试飞情况，即使性能计算正确，中断起飞有时还是有危险的。
这可能由于下列因素：
- 执行中断程序晚。
- 轮胎损坏。
- 刹车磨损或不能正常工作，起始刹车温度高于正常。
- 刹车没有完全应用。
- 跑道摩擦系数比预期的低。
- 全重计算有误。
- 未考虑对准跑道所损失的距离
FCTM有如下解释和要求：
Thorough pre-flight preparation and a
conscientious exterior inspection can
eliminate the effect of some
of these factors.
During the taxi-out, a review of
the takeoff briefing is
required. During this briefing,
the crew s
hould confirm that the computed
takeoff data reflects the actual
takeoff conditions e.g. wind and
runway condition. Any changes to
the planned conditions require
the crew to re-calculate the
take off data. In this
case, the crew should not
be pressurised into accepting a
takeoff clearance before being
fully ready.
Similarly, the crew should not
accept an intersection takeoff
until the take off performance
has been checked.
The line-up technique is very
important. The pilot should use
the over steer technique to
minimizefield length loss and
consequently, to maximize the
acceleration-stop distance available.
决断管理 （FCOM）
■ 100kt以下
中断起飞的决定可由机长根据环境条件作出。
虽然我们不能列出所有原因，但如果能发任何ECAM警告/警戒，机长应慎重考
虑中断起飞。
注： 100kt速度并不是决定性的：选择该值是为了帮助机长决断并避免不必
要的高速中断。
DECISION MAKING （FCTM）
A rejected takeoff is a
potentially hazardous manoeuvre and
the time for decision-making is
limited. To minimize the risk
of inappropriate decisions to
reject a takeoff, many warnings
and cautions are inhibited
between 80 kt and 1 500
ft. Therefore, any warnings
received during this period must
be considered as significant.
To assist in the decision making
process, the takeoff is divided
into low and high speeds
regimes,
with 100 kt being chosen as
the dividing line. The speed
of 100 kt is not critical
but was chosen in order
to help the Captain make
the decision and to avoid
unnecessary stops from high
speed:
Below 100 kt, the Captain
will seriously consider discontinuing
the takeoff if any ECAM
warning/caution is activated.
二、FCOM/FCTM 中断起飞的程序
Rejected take off flow
pattern:（FCTM）
中断起飞标准口令：
RTO PROCEDURE （FCTM）
Should a RTO procedure is
initiated, the following task
sharing will be applied.
(1): Announcing the deceleration means
that the deceleration is felt
by the crew, and confirmed
by the Vc trend on the
PFD. The deceleration may also
be confirmed by the DECEL
light (if the auto brake
is on). However, this light
only comes on when the
actual deceleration is 80 %
of the selected rate, it
is not an indicator of
the proper auto brake operation.
For instance, the DECEL light
might not appear on a
contaminated runway, with the
auto brake working properly, due
to the effect of the
antiskid.
(2):If the takeoff is rejected
prior to 72 kt, the
spoilers will not deploy and
the auto-brake will not
function.
(3):If a rejected takeoff is
initiated and MAX auto brake
decelerates the aircraft, the
captain will avoid pressing the
pedals (which might be a
reflex action). Conversely, if
deceleration is not felt, the
captain will press the brake
pedals fully down.
(4):If takeoff has been rejected
due to an engine fire,
the ECAM actions will be
completed until shutting down
the remaining engines.
三、风险分析
根据前面关于小速度中断起飞的定义和标准操作程序以及对民航界由于小速度中断起飞操作不当而导致的不安全事件分析，得出，在小速度中断时候，面临最大的风险就是：由于方向控制出现问题，导致飞机偏出跑道。
1、受VMCG影响，或跑道为湿跑道或污染跑道，或由于单发导致中断起飞，特别是低速中断时候易导致飞机方向控制困难，甚至偏出跑道。（部分飞行员起飞滑跑单发低速中断没有在控制方向的同时使用刹车）
2、80kt前很多警告和警戒不被抑制，飞行员容易做出错误判断或延时判断。
3、若由于火警导致中断起飞，易忽略应急撤离程序，延误撤离时机。
四、操作建议
1、关于中断起飞的操作简令：
若V1前出现故障或者不正常情况，由___来决定是否中断起飞，若决定中断起飞，喊出“STOP”/“中断”，反推最大，刹车最大。___来监控反推、减速情况，报告ATC；若决定继续起飞，喊出口令“继续”，400FT以下，不做ECAM动作。
2、决策：
根据FCOM，在速度低于100节，若出现任何不正常情况，机长都可以考虑中断起飞
3、角色分配
不论机组如何搭配，都是由符合在左座参与操纵的驾驶员（有资质在左座实行机长职责的驾驶员）执行中断起飞动作，而不论右座是教员、检察员、或者副驾驶。
4、角色转换
只要发出口令“中断”，则操纵权自动交接为左座PF，右座PNF，而不考虑中断之前的角色关系。
5、动作执行：
FCTM有如下描述
To regain or maintain directional
control on the runway, it
is necessary:
‐ To immediately reduce both
thrust levers to IDLE, which
will reduce the thrust asymmetry
caused by the failed
engine
‐ To select both reversers
irrespective of which engine has
failed
‐ To use rudder pedal for
directional control, supplemented by
symmetrical or differential braking
if needed.
The steering hand-wheels may be
used when taxi is reached.
Note: If rudder pedal input
and differential braking are
needed, apply both on the
same side
反推使用：
（1）若执行中断，机长在第一时间按照FCOM程序执行，反推最大。FCTM没有强调最大反推，因此，小速度中断时候，在执行完中断起飞动作后，为了便于方向控制机长可以考虑将反推收回至慢车反推。经模拟机试验，油门杆拉回，实施反推最大后，立即收回至反推慢车，在此期间，反推来不及工作，因此不会对方向控制产生明显的影响。
（2）关于在小速度中断起飞不使用最大反推/以及火警时候不使用最大反推的一些操作，在这里不予以提倡，因为，这样会对飞行机组特别是机长增加额外的判断变量，不利于做出正确的决策，增加了飞行员的反应时间以及飞行员误操作的风险。并且这样的操作动作是与FCOM中断程序违背的。
方向舵、刹车使用
（1）首先应用方向舵来控制飞机方向，若需要，可以采取差动刹车来协助控制方向。驾驶舱准备期间，应
