PBN.3.2 PBN Components - Navigation Specifications Flashcards
Phases of Flight and PBN
What are the different phases of flight and PBN?
En-route:
- Oceanic/Remote
- Continental
Terminal Airspace:
- Arrival/Departure
- SIDs/STARs
- Approach
- simple, non-complex (RNP APCH) with or without vertical guidance, which every operator certified and operationally approved can fly
- complex, demanding (RNP (AR) APCH) requiring specific approval, functionality and training
What are RNAV specifications?
Oceanic/Remote RNAV 10
En-route/Terminal/Approach RNAV 5, RNAV2, RNAV 1
What are RNP* Specifications?
Oceanic/Remote RNP 4
En-route/ Basic RNP 1, RNP APCH,
Terminal/Approach RNP (AR) APCH
PBN Performance Requirements
What does navigation accuracy define?
Defines the Estimation Error on the computed aircraft position: Real aircraft position remains within a determined area 95% of the flight time
What’s navigation accuracy?
It is the radius of this determined area
How much must it be?
Less than 1 x RNP value
What’s integrity?
Ensures a high level of trust in the acft navigation computation
At what percentage does the real acft position remain within a determined area?
99.99% of Flight time
What’s considered in this 99.99%?
Undetected navigation systems malfunctions
Navigation integrity is then…
the radius of this determined area
What are the specific navigation specification parameters determining the integrity?
- Alert Limit
- Time to Alert
- Integrity Risk
- Protection Level
What’s the Alert timit?
Error tolerance not to be exceeded without issuing an alert
- Region (horizontal & vertical) which is required to contain the indicated position with the required probability for a particular navigation mode
- Required ALs depend on the type of operation
What’s Time to Alert?
Maximum allowable time elapsed from the onset of the navigation system being out of tolerance until the equipment enunciates the alert
What’s integrity risk?
Probability that, at any moment, the position error exceeds the Alert Limit
What’s Protection Level?
Statistical bound error computed so as to guarantee that the probability of the absolute position error exceeding said number is smaller than or equal to the target integrity risk
- The region (horizontal & vertical) assured to contain the indicated position. It defines the region where the missed alert requirement can be met
- PLs are computed by the on-board receiver
What happens if during an operation the PLs exceed the required ALs?
The operation cannot continue
What’s VPL only used for?
Operations with vertical guidance (e.g. LPV)
What’s xAL?
Fixed value during operation
What’s xPL?
Value calculated by on-board receiver (varies depending on aircraft and satellite geometry and SBAS corrections)
What’s Navigation Continuity? What does this definition include?
Ensures the computation of navigation information all along the flight.
It includes GNSS services
What documents emerged from the several local initiatives that defined their own requirements to fly some RNAV or RNP concepts?
PBN Manual (ICAO Doc 9613) and
PANS-OPS amendment (ICAO Doc 8168) in order to standarize the PBN concept for area navigation
What’s the diference between the requirements for RNAV and RNP?
Both have the same requirements, but RNP requires to monitor navigation performance in addition, and to alert the non-conformance with the navigation performance criteria.
What’s RNP’s requierement referred as?
On-board Performance Monitoring and Alerting (OBPMA)
What does this differentiation enable aircraft without monitoring function to access?
Several PBN environments
By whom are RNAV operations monitored?
Mainly by ATC
What’s availability?
Percentage of time that the services of the system are usable by the navigator.
Proportion of time during which reliable navigation information is presented to the crew, autopilot, or other system managing the flight of the aircraft
What are other requirements to Achieve Desired Perofrmance Levels?
- Navigation functionalities of the RNAV system: detailed capability of the nav system (such as execution of leg transitions, parallel offset capabilities, holding patterns, navigational databases)
- Choice of navigation sensors
- Aircrew knowledge and training requirements
What’s the Monitoring and Alerting System?
RNP = requirement for the acft avionics to provide on-board performance monitoring and alerting
RNAV does not require this
What are the acft systems that are capable of performance monitoring and alerting called?
RNP systems
What does the on-board performance monitoring and alerting provide to the flight crew when the required lateral track accuracy limiti stipulated for the ATS route leg is exceeded?
Unable RNP
What’s the historical difference between RNAV and RNP capable aircraft?
On-board performance monitoring and alerting (OBPMA)
What’s this difference in reality?
Airframe
Aircraft built in the 1980s and 1990s have less functionality and are considered RNAV acft, whereas acft built after 2000, have significantly more functionality and are considered RNP capable
Where can we find the details of OPMA?
Volume II, Part A of the PBN Manual
Aircraft Functionality
What are all acft able to do when area navigation capable?
Flyover turn
How does the aircraft perform the flyover turn?
Acft starts to turn onto the next leg of the ATS route as it passes over the waypoint
What’s the disadvantage with a flyover waypoint?
Acft must transit over wpt before turn is initiated and then recover onto the next desired track
Recovery back on to the intended path after the turn initiation may not be consistent due to different acft performance
How does an acft perform a fly-by?
Aircraft’s RNAV system anticipates the turn
On what does the turn initiation depend?
Max bank angle
Speed
Altitude
Turn angle
By what are all turns affected?
TAS and wind velocity. Therefore, the performance of these turns will not be the same
What’s the earliest the turn can be initiated?
20 NM prior to the waypoint
What are fixed radius used for?
To ensure predictable and reliable track keeping in the turn
What will the aircraft fly with a fixed radius?
Consistent, highly repeatable ground track
Which acft are highly likely to have this functionality today?
Newer generation, RNP capable, acft
How does the acft do a turn with a fixed radius?
Acft commences the turn at a defined point and then automatically adjusts the Angle of Bank to maintain a constant radius from a specified point
In which ways is fixed radius performance achieved?
Depending on the phase of the flight:
Radius to Fix (RF)
Fixed Radius Transitions (FRTs)
What are these functionalities associated to?
RNP Specifications