Performance Based Navigation (PBN), (ppt Jan '18) Flashcards
Preparing PBN for daily operation or sim detail
Which, as EZY pilots, PBN procedures are we allowed to perform?
- RNAV-5
- RNAV-1
- RNAV (GNSS) approaches
- NPA Overlay approaches
What is RNP?
What is RNAV?
What does it mean?
- Required Navigation Performance
- Area Navigation
- Specification regarding the above means that one has to fly to the lateral navigation accuracy required. RNP-X, where X nm has to have an accuracy >95% of the time
How is obstacle clearance guaranteed with regards to RNP?
e.g. If flying RNAV-5:
The containment area is 2 x 5 Nm = 10 Nm deviation from either side of the RNAV track
Why is it a problem for an RNAV approach to loose GPS or DME/DME updating?
“GPS PRIMARY or DME/DME updating available” means that the estimated position error (EPE) will be < 0.3Nm.
If you loose them you can’t guarantee the required accuracy
What does GNSS stand for?
What does it do?
Global Navigation Satellite System (GNSS)
It is a Global Position System which is compatible with the onboard GPS systems
What does GPS PRIMARY indicate?
That there is sufficient GPS/GNSS coverage/validity for the 2 onboard GPS receivers.
It is the primairy means of position determination.
(Receiver Autonomous Integrity Monitoring: RAIM)
- What does RNAV-5 mean?
- What is a different indication for RNAV-5?
- To which part of a flight does it apply?
- Required Navigation Performance (RNP) 5.0 Nm required
- B-RNAV (Basic RNAV)
- It’s the EN-ROUTE, above MFA, and some arrivals and departures
- What does RNAV-1 mean?
- What is a different indication for RNAV-1?
- To which part of a flight does it apply?
- Required Navigation Performance (RNP) 1.0 Nm required
- P-RNAV (Precision RNAV)
- Can be used for all flight phases EXCEPT final approach
(ALL EZY A/C’s are RNAV-1 COMPLIANT!)
- What does RNP-1 mean?
- How does it differ from RNAV-1/P-RNAV?
- To which part of a flight does it apply?
- Required Navigation Performance (RNP) 1.0 Nm required
- GNSS and on-board alerting are required (GPS PRIMARY LOST/NAV ACCUR DOWNGRAD) and it may also make use of Radius to Fix (RF) legs
- Can be used for all flight phases EXCEPT final approach
(ALL EZY A/C’s are RNP-1 COMPLIANT!)
What is the main advantage of being able to fly RNAV approaches?
Greater flexibility to operate to destinations where ground-based NPA aids would preclude a landing
What is standard RNAV-5 airspace?
ECAC (European Civil Aviation Converence) airspace > FL95
What are the only items that you may revise in the NAV database with regards to RNAV?
Speed and Altitude constraints
What is the maximum acceptable variation for normal navigation?
- Up to 3 degrees is acceptable
If GNSS is required, what should you check is available?
- GPS PRIMARY available and associated RAIM coverage
- Determine and check/set RNP and confirm NAV ACCUR HIGH
What are the different RNP default values for which location/flight phase?
En-route / Outside Terminal or Appr Area / 2.0 Nm Terminal Area / < 15.000’ / 1.0 Nm Approach / < 5 Nm to the first waypoint of the Final Appr / 0.3 Nm (GPS) or 0.5 Nm (others)
Is use of the Flight Director mandatory when flying a RNAV or RNP SID/STAR/Transition?
Yes
Is use of the AP mandatory when flying a RNAV or RNP SID’s/STAR/Transition?
No
When are you allowed to accept direct routings during SID’s/STAR/Transition?
Only if you are above the MFA for that specific flight phase
If the SID chart states GNSS or DME/DME required and you loose GPS, can you continue?
Yes, but it is sensible to inform ATC and consider GPS necessity for the continuation of the flight
If a SID chart states that it required RF, RNP 1.0 and GNSS, can we fly the departure?
Yes, EZY A/C’s comply with all three elements needed.
What does RF stand for?
Radius Fix (all EZY A/C’s are RF compliant)
It are turns based on radial distances from a beacon or fix
In which cases do you need to advise ATC:
“Unable RNAV due equipment, request re-clearance”
and get a new lateral and vertical clearance?
- NAV ACCUR DOWNGRAD (on MCDU and ND) on both sides
- FMS1/FMS2 POS DIFF (on MCDU and ND)
- NAV FM/GPS POS DISAGREE (on ECAM)
- Map shift
- Loss of NAV mode (also causing loss of CLB/DES mode)
- Loss of specified navigation source for particular procedure
- During RNP-1: XTK on ND >0.5 Nm in RF legs
NOTE: if GPS PRIMARY LOST in case GNSS is NOT required you may continue if NAV ACCURACY is HIGH!!! (due to DME/DME operable for example)
If your destination, only has an RNAV approach available, what must be your consideration with regards to the destination alternate?
The destination alternate must at least have an approach based on conventional nav aids and the weather 1 hour prior and after ETA must be at or above the associated minima.
What is the latest point for intercepting the final approach for an RNAV approach procedure?
The approach trajectory MUST be laterally and vertically intercepted BEFORE the FAF
What is the maximum vertical deviation on an RNAV (GNSS) approach with FINAL APP (VNAV/LNAV)?
3/4 index up or down (75ft)
(One dot is 100 ft)
How do you fly an RNAV approach if temperature prohibits the managed/managed mode FINAL APP?
- Engage NAV and use FPA for final descent
- Monitor descent profile (alt/dis) and adjust accordingly (0.1 degree is 100’/Nm)
When do you need to discontinue the approach on an RNAV (GNSS) approach?
If visual references CANNOT be obtained:
- GPS PRIMARY LOST on both ND’s (CLIC, CLIC, CLIC)
- XTK >0.3 Nm
- NAV FM/GPS POS DISAGREE (on ECAM)
- NAV ACCUR DOWNGRAD (on BOTH FMGS!!!!!!)
or If flying in FINAL APP:
- V/DEV > 3/4 DOT (75’)
What is an NPA Overlay Approach?
A conventional NPA approach (e.g. VOR/DME, NDB/DME) which are flown using RNAV AP/FD modes.
What must be available according to NPA SOP’s to fly an NPA Overlay?
- GPS MUST be available
- What are the 2 techniques to fly an NPA Overlay?
- FINAL APP (decelerated approach is standard technique)
- NAV/FPA (stabilized approach is recommended technique) (check OMB)
What must be displayed and checked during a NPA Overlay?
- Raw data (within 5° track deviation)
- Altitude v.s. distance
On a NPA Overlay approach you loose GPS PRIMARY after commencement of the approach.
How do you continue?
NAV and FINAL APP can be used to continue the approach (based on database/DME/DME/tuned aids) provided RAW DATA indicates correct navigation
On a NPA Overlay approach you get an ECAM: FM/GPS POS DISAGREE?
How do you proceed?
Use selected/selected (TRK/FPA or TRK/V/S) to continue the approach
During a NPA Overlay you loose raw data and/or you are out of the 5 degrees left/right inbound course. What do you do?
Discontinue the approach unless visual references are obtained
Down to which MDH/DH is FINAL APP with GPS PRIMARY demonstrated?
250 ft barometric
What is needed to operate in NAV in the terminal area?
- GPS PRIMARY or
- HIGH ACCUR is displayed
and appropriate RNP is displayed or enterend on MCDU
- NAVAID raw data is monitored
How are you allowed to fly a single engine, NPA on an A319?
Only FD use is permitted It is not permitted to use the AP to perform NPA’s in: FINAL APP, NAV V/S, NAV/FPA
What does it mean when you fly something “managed”?
What does it mean when you fly something “selected”?
- Managed means: via the FMGC database (NAV/X or FINAL/APP)
- Selected means: via pilot input (TRK/HDG, FPA V/S)
How are you allowed to fly a single engine, NPA on an A320?
In the same ways you fly a normal, 2 engines NPA, AP on
What are the 3 components of Performance Based Navigation (PBN)?
- Navigation Specification
- Navigation Infrastructure
- Navigation Application
What is meant with Navigation Specification?
Aircraft and Pilot requirements needed within a defined airspace
What is meant with Navigation Application?
Application of the Nav Specification and Infrastructure to routes, procedures and airspace
What is meant with Navigation Infrastructure?
Ground and/or Space based navigation aids
What is the RNP value compared with to establish accuracy?
- The Airbus computes an EPE (Estimated Position Error) which is compared to the RNP value
- EPE ≤ RNP = Accuracy HIGH
- EPE ≥ RNP = Accuracy LOW
If GPS PRIMARY or DME/DME is available, which EPE value is normally achievable?
EPE < 0.3 Nm (accuracy HIGH)
What are the most common Navigation Infrastructure components?
- GNSS (Global Navigation Satellite System)
- IRU (Inertia Reference Unit)
- DME/DME
What elements improve the accuracy of GNSS?
- Space Based Augmentation System (SBAS)
Accurately surveyed ground stations measure signal errors. These corrections are than transmitted to SBAS satellites which then transmit correting signal to the aircraft
- EGNOS
European version of SBAS with LPV minima. Not currently authorized
- Ground Based Augmentation System (GBAS)
Accurately surveyd ground stations measure signal and generate correcting sighnals which are transmitted to receivers in the local area over VHF
- Receiver Autonomous Integrity Monitoring (RAIM)
System that predicts the availability of RAIM and thus NAV availability
If talking about PBN with regards to the enroute segment, what RNAV or RNP values are associated with this part of the flight?
- RNAV 10 and RNP 4 are both utilised in oceanic and remote areas
- RNAV 2 and RNP 2 can also be used for oceanic and remote areas enroute
- RNAV 5 (also know as B-RNAV in EU) is the enroute standard
What is the difference between RNAV and RNP?
- RNP requires an on-board navigation perfromance monitoring and alerting system,
e. g. GPS PRIMARY LOST or NAV ACCUR DOWNGRAD - RNAV does NOT require a monitoring and alerting function
If talking about PBN with regards to the Departure and Arrival segment, what RNAV or RNP values are associated with this part of the flight?
- All arrivals above MFA are RNAV 5, unless otherwise stipulated
- RNAV 1 and RNP 1 can be used for departures and arrivals below MFA
- Some Go Arounds require RNAV 1
If talking about PBN with regards to the Approach segment, what RNAV or RNP values are associated with this part of the flight?
- RNP APCH require at least navigation specification 0.3 Nm
- RNAV Visual
What is a 3D approach?
- A 3D approach is any approach flown fully managed (includes ILS)
If only LNAV minima available, can you still fly fully managed?
Yes but to higher minima
What indication on your PFD is caractaristic for a 3D approach?
A final approach data-block (brick) will be on display for all 3D approaches (except ILS)
What is meant by a 2D approach?
When do we normally expect to fly this?
- An approach flown with selected vertical guidance (including LOC approach).
- It is generally used if temperature is below limit defined on the chart.
When flying a 2D approach due to low temperatures what has to be done with the minima?
If the OAT is below limits a correction needs to be applied to:
- The check altitudes
- LNAV minima