>> Tuesday, June 15, 2010


This programme monitors aircraft delays, cancellations and significant events; giving alerts when adverse trends are identified. 



The Dispatch Reliability programme is meant to
a)      Provide performance measurement and monitoring for dispatch reliability and cancellations for the use of management.
b)Allow analysis of trends to identify and investigate technical problems for solutions.
c)      Permit analysis to spot problematic aircraft systems or components.
d)      Identify areas that require investigation and/or improvements in aircraft maintenance efficiency or effectiveness.
e)      Record significant events and their basic causes for preventive action, and for future reference.
Overall objective is to reduce delays, cancellations, and major disruptions caused by aircraft defects thereby reducing costs and improving customer service.  It helps the identification and elimination of deficiencies affecting aircraft operations. 



a)      Only delays, cancellations and significant events related to aircraft mechanical defects or failures shall be included for this programme.
b)      All revenue departures (at main base and line stations) which are delayed based on Scheduled Time of Departure (STD) arising from mechanical defects shall be captured.  Only delays exceeding 15 min. shall be counted for performance statistics.
c)      A revenue flight cancellation is considered as a delay.
d)      Significant events shall also be captured as part of this programme.  They
1.       Normally have significant impact to customer service e.g. prolonged AOG, unscheduled engine change, in flight shutdown, ground incidents;
2.       include events that require mandatory reporting by local authority e.g. In flight engine shutdown (IFSD), aborted take-off (ATO), excursion from runway, etc.  Particular attention shall be paid to engine related defects/events.
3.       May or may not cause delays/cancellations.



a)      Maintenance Control Centre (MCC) shall capture all necessary information for this programme in a database viz.
1.      Aircraft registration
2.      Flight number
3.      Date and station
4.      Length of delay
5.      Problem description
6.      Findings, in particular cause of defect if identified
7.      Corrective action taken
8.      Component replacement information
9.      Relevant contributing factors
10. ATA code/Incident code/Delay code
b)      Engineering shall obtain from Flight Operations and Technical Records the total number of revenue departures and operating statistics per month.
c)      MCC shall be responsible for ensuring good complete information for delays, cancellations and significant events are captured on timely basis.
d)      MCC shall capture the delay and cancellation data promptly in a computer database viz. AiMs (Aircraft Maintenance System).
e)      MCC supervisor shall vet through the information captured for completeness, and contact relevant person(s) for more information as required as promptly as possible.
f)       The root or most probable cause for each delay and cancellation shall be determined as far as possible and coded to allow easy analysis.
g)      Where the delay or cancellation is due to multiple defects, the defect that caused the longest delay shall be used as the main reason for that event.
h)      Urgent actions to prevent recurrence of defects or significant events shall be undertaken by respective departments, and reported during the monthly meeting.
i)        Approval holders reporting delays and cancellation shall use Delay Report Form.
j)        Approval holders reporting significant events shall use the same Delay Report Form for simplicity, but shall indicate “Prolonged grounding/Incident” on the form.
k)      MCC shall distribute to relevant parties monthly summaries of delays and cancellation produced by the database.



a)      The primary performance indicator used is dispatch reliability while cancellation rate per 1000 FH also provides indication of overall fleet performance.  Engineering shall calculate these on a monthly basis.  They may also be calculated by the computer system automatically once the system is verified to be reliable.
b)      The other information captured e.g. cancellations, major interruptions, ground incidents etc may be used qualitatively as necessary.
c)      Other indicators such as delays and cancellations per 1000 FH for specific aircraft registration may also be developed and used to compare aircraft performance.



a)      Dispatch reliability shall be calculated based on industry practices as described in WATOG (World Airline Technical Operations Glossary).
b)      Dispatch reliability is
(No. of revenue dep. for period – No. of rev. dep. delayed>15 min.) x 100%
(Number of revenue departures for the period)

c)      Flights that are delayed as a consequence of a delayed preceding flight shall not be counted.
d)      Flights that are retimed at least 4 hours in advance shall not be counted as delays.
e)      Cancellation rate per 1000 FH is
No of revenue flights cancelled in period x 1000
Fleet total flight hours for period

f)       Delays/cancellation used for calculating dispatch reliability/cancellation rate shall exclude those attributed to deficiencies other than aircraft itself e.g.
late arrival of flight or ground crew,
flight crew querying deferrable defect that was subsequently accepted,
adverse weather or air traffic problems,
loading delays,
spares late delivery from warehouse,
ground support equipment failure,
obvious failure of the human element,
deliberate engineering management decision to rectify deferrable defects.
g)      Delay codes used in the database categorise delay causes when the delay is not attributed to the aircraft failures. 


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