2. CONTENTS
WHAT IS TORA, TODA, ASDA?
INTRODUCTION AND HISTORY.
DEFINTIONS.
BALANCED AND UNBALANCED FIELD.
GO OR NO GO DECISION.
PROBLEMS IN RTO.
CONCLUSION.
REFERNCES.
3. WHAT IS TORA, TODA, ASDA?
TORA- TAKE OFF RUN AVAILABLE
The runway length declared available and suitable for the ground
run of an airplane taking off.
TODA- TAKE OFF DISTANCE AVAILABLE
The length of the TORA plus the length of the clearway, if
provided.
ASDA- ACCELERATE STOP DISTANCE AVAILABLE
The TORA plus the length of the stopway, if provided for the
acceleration and deceleration of an airplane aborting a takeoff.
LDA- LANDING DISTANCE AVAILABLE
It is the runway length declared available and suitable for
landing an airplane.
4. HISTORY AND INTRODUCTION
As we all know each takeoff includes the possibility
that the pilot needs to stop the aircraft and reject the
takeoff. Aborting at a high speed can lead to serious
accident. In 1989, in reaction to a number of takeoff
accidents resulting from improper rejected takeoff
decisions and procedures, a joint FAA/industry
taskforce studied what actions might be taken to
increase takeoff safety. From this Boeing led an
industry wide effort to develop a training aid.
The result was a publication entitled Takeoff Safety
Training Aid and a flight crew briefing video entitled
Rejected Takeoff and the Go/No Go Decision released
in 1993.The goal of the Training Aid was to minimise
the probability of RTO related accidents.
5. HISTORY AND INTRODUCTION
With the growth in air traffic and enhancement of
capacity at all major airports across the country, it had
become vital that runway safety programmes were put
in place to prevent runway overrun that may lead to
incidents/ accidents.
This lead to the idea of increasing the length of
runway in case of an aborted take off on take off roll
for go or go no decisions.
6. DEFINITION
STOPWAY- An area beyond the takeoff runway that is at
least as wide as the runway, is centred upon the extended
runway centreline, and is able to support an airplane
during an aborted takeoff without causing structural
damage to the airplane.It must not be used for landing
calculations.
CLEARWAY- An area beyond the takeoff runway that is
under the control of airport authorities where terrain or
fixed obstacles may not extend above specified limits. It is
not required to be able to support the weight of the
aeroplane, it must only be free of obstacles.
10. BALANCED & UNBALANCED
FIELD
A balanced field is a where the accelerate-stop distance is
equal to the take off distance for the aircraft weight,
engine thrust, aircraft configuration and runway condition.
It is the shortest field length at which a takeoff can be
performed.
An unbalanced field is where there is stopway or clearway
or both are available.
13. GO or NO GO DECISION
The decision of whether to STOP or GO, are always
performed by the Captain, because this decision and/or
action may significantly impact on flight safety. The
Captain must, therefore, keep his/her hands on the
throttle/thrust levers until the aircraft reaches V1 ,
regardless of whether he/she is PF or PNF(PM).
If a malfunction or problem occurs during the takeoff roll,
the Captain will call out “STOP”, to confirm an RTO
decision. If the Captain calls out “GO”, this confirms that
he/she does not intend to reject the takeoff.
14. HIGH SPEED & LOW SPEED
RTO
The takeoff roll is divided into a low and high speed
segment. If the aircraft speed is less than 100 knots, the
aircraft is considered to be in the low speed segment and
an RTO decision leads to a low risk maneuver. If the
aircraft speed is above 100 knots, the aircraft is considered
to be in the high speed segment and an RTO decision may
potentially involve more risks. The speed of 100 kt was
chosen to help the captain make his/her decision and avoid
unnecessary RTOs at high speeds
15. AT V1 SPEED
At V1, the Captain’s hand comes off the thrust
levers/throttles, and the PF can continue the takeoff even
if a malfunction or a problem is then detected, because it
may not be possible to stop the aircraft on the remaining
runway length.The Captain can consider to reject a takeoff
when the aircraft is above V1, only in the event that the
aircraft is not able to ensure a safe flight.
16. PROBLEMS IN RTO
Most pilots have difficulties in recognising unsafe to fly
conditions.
The Detection-Decision-Action process still takes a lot of
time.
There is confusion between operating procedure and
general procedure.
17. TYRE FAILURE ON THE
TAKEOFF ROLL
Failure of a tyre will result in a longer than calculated
stopping distance due to the loss of braking force on
the associated wheel. It also has the potential to lead
to additional tyre failure if the take off is rejected. One
aircraft manufacturer, Airbus, has made a generic
recommendation that, for a single tyre failure with no
evidence of collateral damage, the takeoff be
continued if the speed is greater than V1 minus 20
knots.
18. CONCLUSION
Runway Excursions arising from Rejected take offs can
therefore usually be avoided with plenty of runway length
available
but if there is a limit on runway length
then operating procedures for the aircraft should be
applied each and every time along
with cross checking take off performance calculations with
the corresponding thrust setting to have to safe RTO.
19. The most effective way for an Operator to ensure that
flight crew are likely to respond to a rejected take off
decision and its execution in the expected way is to brief
the pilot about every situation and practice about the same
situation in simulator training.
