When is On-Time, On-Time?
Join Date: Jul 2004
Location: London
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On Time Tolerance, Airborne Time, Arrival Delays, Delay Manipulation, Delay Analysis
This post got somewhat out of hand has been divided into:
On Time Tolerance, Airborne Time, Arrival Delays, Delay Manipulation, Delay Analysis (or Lack of it) and Finally.
On Time Tolerance:
Each airline sets its own 'On time Tolerance' in some cases varying it between Short Haul and Long Haul Operation. Whilst there are anomalies, in general the ranges are:
Zero Tolerance - The Aircraft Starts to Move off Stand on Time, otherwise a delay has to be reported.
+2 to +5 Minutes- Used to be the most used set of ranges and suspect still is
+ 5 to + 15 Minutes - Some Long Operators set wider ranges..
Doors Close Time: If the Doors Close at the required time before STD, this lets the Traffic Handling Sections off the 'hook' at any delay assessment, but is otherwise is not used in Operational Messages:
Ranges tend to be:
-2 to -7 Minutes and again the same airline can use different ranges for Short Haul and Long Haul.
Airborne Time:
Whilst Airlines have standard Taxy Times for each Airport and occasionally for individual stands, it is often very difficult for a Ground Handling agency to pinpoint why an individual departure was late getting Airborne especially at busy Airports.
If general Congestion, or some other problem affecting all departures, then fine, but often a single departure will be unlucky and get held up.
ACARS if fitted or traditional Monitoring will tell the Agency Operations Centre of a late Airborne, but finding out exactly why, will take time they don't have.
Arrival Delays:
I have only encountered one Airline that seriously monitors Enroute and Arrival Delays in real time, although I have also encountered several that do post flight Analysis when it is obvious there is a major discrepancy between Departure, Estimated Flight time and Arrival.
If a single Route and/or Period of the Day Affected, a special one off project has proved useful in actually get the Schedule Changed.
Delay Manipulation
For Airside Dispatchers, ‘honesty is the best policy, but the cost can be too high’. Hence the traditional use of the ‘Rubber Watch’, which can also be applied by the Flight Deck Team.
Even ACARS can, as others have stated, be manipulated, although if to be successful requires the cooperation of the Flight Deck and not releasing the parking brake before doors close.
In the new No-Dispatcher systems being introduced by some Major Airlines, where each section involved has to ‘hit its marks’, I suspect there are a variety of new ways being explored to avoid being deemed the cause of delay.
Some level of Delay Manipulation is always going to exist, but it is going to be much more prevalent, when being deemed the Cause of Delay is translated to being Automatically Blamed for the Delay
Delay Analysis (or lack of it)
Delay recording, A Maximum of 4 Delay Reasons is normal, although at Main base this can get much more complicated in apportioning the exact section(s) involved.
Unfortunately these Delay records are often used in playing the Blame Game, rather than reading the Airside Dispatchers Notes, or any Post-Flight review and of course the Airline may penalise the Handling Agency based on the Delay Information sent in the MVT/MVA/OOI Message, without actually finding out the details.
I was once peripherally involved (getting the reporting module of a system to automatically do what was required) in a project to rigorously investigate primary delay causes from Main base and drill down into exactly why they were occurring.
Once the Airside Dispatchers realised their reports were being taken seriously, the quality of information rose significantly. The project actually revealed some very useful results and changes were made in the internal departments involved and some ultimately less useful discussions with the Airport Authority and ATC were held.
Finally:
Using delay codes as the be all and end all of a Blame Game, or Financial Penalty System actually has a negative effect on improving performance. Unfortunately the Blame Game is easy to play (I'll accept this delay, if you take that one, deal done) and the Financial Penalty Systems provide a stick to beat the Agencies with, so these practises tend to become institutionalised in organisations and much to the frustration of the frontline staff as their reports on what/why and how a delay actually came about are ignored. After a while this results in reporting becoming either terse to the point of being useless, or if time allows a rant which relieves the frustration, but can be safely written, because it won't be read!
On Time Tolerance, Airborne Time, Arrival Delays, Delay Manipulation, Delay Analysis (or Lack of it) and Finally.
On Time Tolerance:
Each airline sets its own 'On time Tolerance' in some cases varying it between Short Haul and Long Haul Operation. Whilst there are anomalies, in general the ranges are:
Zero Tolerance - The Aircraft Starts to Move off Stand on Time, otherwise a delay has to be reported.
+2 to +5 Minutes- Used to be the most used set of ranges and suspect still is
+ 5 to + 15 Minutes - Some Long Operators set wider ranges..
Doors Close Time: If the Doors Close at the required time before STD, this lets the Traffic Handling Sections off the 'hook' at any delay assessment, but is otherwise is not used in Operational Messages:
Ranges tend to be:
-2 to -7 Minutes and again the same airline can use different ranges for Short Haul and Long Haul.
Airborne Time:
Whilst Airlines have standard Taxy Times for each Airport and occasionally for individual stands, it is often very difficult for a Ground Handling agency to pinpoint why an individual departure was late getting Airborne especially at busy Airports.
If general Congestion, or some other problem affecting all departures, then fine, but often a single departure will be unlucky and get held up.
ACARS if fitted or traditional Monitoring will tell the Agency Operations Centre of a late Airborne, but finding out exactly why, will take time they don't have.
Arrival Delays:
I have only encountered one Airline that seriously monitors Enroute and Arrival Delays in real time, although I have also encountered several that do post flight Analysis when it is obvious there is a major discrepancy between Departure, Estimated Flight time and Arrival.
If a single Route and/or Period of the Day Affected, a special one off project has proved useful in actually get the Schedule Changed.
Delay Manipulation
For Airside Dispatchers, ‘honesty is the best policy, but the cost can be too high’. Hence the traditional use of the ‘Rubber Watch’, which can also be applied by the Flight Deck Team.
Even ACARS can, as others have stated, be manipulated, although if to be successful requires the cooperation of the Flight Deck and not releasing the parking brake before doors close.
In the new No-Dispatcher systems being introduced by some Major Airlines, where each section involved has to ‘hit its marks’, I suspect there are a variety of new ways being explored to avoid being deemed the cause of delay.
Some level of Delay Manipulation is always going to exist, but it is going to be much more prevalent, when being deemed the Cause of Delay is translated to being Automatically Blamed for the Delay
Delay Analysis (or lack of it)
Delay recording, A Maximum of 4 Delay Reasons is normal, although at Main base this can get much more complicated in apportioning the exact section(s) involved.
Unfortunately these Delay records are often used in playing the Blame Game, rather than reading the Airside Dispatchers Notes, or any Post-Flight review and of course the Airline may penalise the Handling Agency based on the Delay Information sent in the MVT/MVA/OOI Message, without actually finding out the details.
I was once peripherally involved (getting the reporting module of a system to automatically do what was required) in a project to rigorously investigate primary delay causes from Main base and drill down into exactly why they were occurring.
Once the Airside Dispatchers realised their reports were being taken seriously, the quality of information rose significantly. The project actually revealed some very useful results and changes were made in the internal departments involved and some ultimately less useful discussions with the Airport Authority and ATC were held.
Finally:
Using delay codes as the be all and end all of a Blame Game, or Financial Penalty System actually has a negative effect on improving performance. Unfortunately the Blame Game is easy to play (I'll accept this delay, if you take that one, deal done) and the Financial Penalty Systems provide a stick to beat the Agencies with, so these practises tend to become institutionalised in organisations and much to the frustration of the frontline staff as their reports on what/why and how a delay actually came about are ignored. After a while this results in reporting becoming either terse to the point of being useless, or if time allows a rant which relieves the frustration, but can be safely written, because it won't be read!
