36TH ANNUAL CONFERENCE, Taipei, Taiwan, 17-21 March 1997WP No. 109Notification of Aircraft Equipment on Flight Plans |
At present the flight plan is the principle means used to convey the details of the flight to the controller, frequently through the flight plan processing equipment used by many ATC systems. Technical information such as the type of aircraft and the navigation equipment fitted is also passed in this way. This paper highlights the limitations of this system and the increasing problems using this system for disseminating this information.
It is IFATCA policy for the information required by the controller to be disseminated by means of the flight plan, and this was recently confirmed when policy on MLS was adopted to require the type of MLS equipment to be included on the flight plan.
Since this policy was adopted, it has now become clear that there will be a huge amount of modified and additional equipment being installed in aircraft over the next few years. This would appear to create increasing problems with using the flight plan to pass this information to ATC.
The flight plan system for disseminating information has already been found to be lacking in some circumstances. This has been particularly noticed with aircraft type changes where operators either fail to send change messages, or they are considered to be unimportant and are not disseminated within the ATC system.
This problem will increase with new equipment such as MLS and GNSS being installed where aircraft of the same type may have different landing capabilities depending on the type of equipment installed. Change messages do not regularly get sent when an aircraft changes from e.g. a B737 to a B767 and this problem will increase when an aircraft fitted with e.g. GNSS is changed to an apparently identical aircraft of the same type, but fitted with e.g. MLS.
This problem becomes more complex as the amount of equipment increases. There will be requirements for GNSS, RVSM, 8.33kHz RTF, RNAV, datalink and possibly other requirements.
The flight plan equipment field is currently limited to one alphabetical character and most characters have already been used. There is an additional problem that the single character field can only identify one type of equipment e.g. MLS. The IFATCA policy requires both Basic and Advanced equipment to be shown. Although it appears that this requirement will not materialise, it would not be possible to show both types of equipment as only one character is available.
This problem will have to be faced with GNSS, where it is quite likely that several types of equipment will be in use. It could be anticipated that there might be as a minimum; en-route navigation only; non-precision approach; CAT 1 WAAS; Cat II/III LAAS. As the specifications have not been finalised, these types can only speculated. There may also be other types of equipment to consider.
A recent requirement has arisen to display two type of ILS receivers. During the transition period to new FM immune ILS receivers, both immune and non-immune receivers will be in service and in some circumstances ATC will have to treat aircraft differently according to the type of receiver fitted. It is not possible to display this on the flight plan in the equipment field as only one character is available. At present the only option would be to display this information in field 18, as is planned for 8.33 kHz RTF spacing.
This problem will occur again as other types of equipment are considered such as GNSS, RVSM, and datalink.
The use of field 18 is not an acceptable solution to this problem. The field is not processed in the same manner as the remainder of the flight plan. Some systems do not process it at all. It may not be displayed to the controller or else may only be in the form of a remark.
There are certain equipment requirements for each portion of airspace. The need to specify a large amount of equipment for each airspace and each type of operation will create increasing demands as the complexity of equipment increases. It will frequently be sufficient for the controller to know that the aircraft is adequately equipped to fly in this area. He will not need to know each specific item of equipment. This is already a principle of RNP. This principle should also be the basis of flight planning, that the aircraft is equipped for the flight unless a lack of equipment is specified in the flight plan.
There are 2 potential solutions to this problem. The some cases RNP may remove the need for the controller to know which type of equipment the aircraft is using. This may solve the problem in some cases, but where a number of RNP=92s are used in the same area it may only move the problem from one place to another if the controller needs to know what standard of RNP the aircraft is capable of. Progress to RNP is also along way off in many areas.
The second solution is datalink, whereby information on the type of equipment fitted is downlinked to the controllers workstation and could be accessed by the controller when required. This would be the ideal solution, but would only really be helpful if the majority of aircraft were equipped and this is a long way off.
Conclusion
The need for accurate and reliable information on the aircraft equipment will increase with the introduction of new equipment.
The existing ICAO Flight Plan Form is proving inadequate to display the information on aircraft equipment required by ATC. At best, equipment such as 8.33kHz is using field 18. In some cases it has not been possible to display the equipment state as we would wish.
The basis of equipment carriage on the flight plan should be that the aircraft is suitably equipped for the intended flight and that only when the aircraft lacks the required equipment should this be listed on the flight plan.
Future developments such as RNP and datalink may assist with this problem but large-scale implementation is a long way off. The problem is now becoming urgent due the large number of equipment changes being implemented within the next few years.
There is a requirement for ICAO to review and update the current flight plan form with particular reference to equipment carriage.
Last Update: September 28, 2020