bsevenfour
4th Aug 2002, 04:58
I'm just trying to clarify in my mind requirements for RNAV arrivals and departures, particularly since a lot of airports now are producing RNAV arrivals and departures.
From what I understand certain areas around the globe have different RNP (Required Navigation Performance) requirements, for example in Europe the standard is RNP 5 for basic radio nav (BRNAV) whereas transoceanic the RNP requirement reduces to 10 to take account of the lack of radio updating. The RNP figure basically means that the aircraft should have a calculated position error less than the RNP requirement. Most of the modern aircraft generate figures for their actual navigation performance based on what equipment they have available i.e. IRS , GPS and what updates are available to these positions. The generated figure means that the position error between the actual and estimated aircraft position will be within this figure 95% fo the time. As long as this actual navigation performance figure is less than the RNP requirement and you have an operating FMC which can store the RNAV routes and waypoint positions you are good to fly on RNAV tracks and to accomplish RNAV arrivals and departures.
If anyone has any corrections or additions they think should be made to the above I would be glad to hear it.
Now for some questions.
- While I understand Europe has an RNP 5 requirement does this apply only to the upper airways or does it apply also to all the RNAV arrival and departures to European airports as a 5 mile postion error obviously becomes more significant when flying an arrival then at altitude on an airway ? I know on the Boeing , I presume it's the same on the Airbus, that the default RNP figure above which an alert is usually generated reduces to smaller values when the aircraft enters more critical stages of flight.
- If the RNAV requirements for arrivals and departures are different from this blanket value of 5 where does one find them ......Any links or references would be greatly appreciated.
- Outside of Europe where RNAV arrivals and departures are also available how does one go about finding the RNP requirements for them or is there an ICAO basic standard that has to be met for all RNAV arrivals and departures. Again any references on this issue would be greatly appreciated.
- Finally in the States does anyone have any FAA references concerning RNAV arrivals and departures and the RNP requirements accompanying them ?
Thanks for any help on the above issues.
From what I understand certain areas around the globe have different RNP (Required Navigation Performance) requirements, for example in Europe the standard is RNP 5 for basic radio nav (BRNAV) whereas transoceanic the RNP requirement reduces to 10 to take account of the lack of radio updating. The RNP figure basically means that the aircraft should have a calculated position error less than the RNP requirement. Most of the modern aircraft generate figures for their actual navigation performance based on what equipment they have available i.e. IRS , GPS and what updates are available to these positions. The generated figure means that the position error between the actual and estimated aircraft position will be within this figure 95% fo the time. As long as this actual navigation performance figure is less than the RNP requirement and you have an operating FMC which can store the RNAV routes and waypoint positions you are good to fly on RNAV tracks and to accomplish RNAV arrivals and departures.
If anyone has any corrections or additions they think should be made to the above I would be glad to hear it.
Now for some questions.
- While I understand Europe has an RNP 5 requirement does this apply only to the upper airways or does it apply also to all the RNAV arrival and departures to European airports as a 5 mile postion error obviously becomes more significant when flying an arrival then at altitude on an airway ? I know on the Boeing , I presume it's the same on the Airbus, that the default RNP figure above which an alert is usually generated reduces to smaller values when the aircraft enters more critical stages of flight.
- If the RNAV requirements for arrivals and departures are different from this blanket value of 5 where does one find them ......Any links or references would be greatly appreciated.
- Outside of Europe where RNAV arrivals and departures are also available how does one go about finding the RNP requirements for them or is there an ICAO basic standard that has to be met for all RNAV arrivals and departures. Again any references on this issue would be greatly appreciated.
- Finally in the States does anyone have any FAA references concerning RNAV arrivals and departures and the RNP requirements accompanying them ?
Thanks for any help on the above issues.