Approaches: RNAV/RNP Flashcards
How many Satellites are needed for RAIM to function properly?
- 5 Sats
- 4 Sats, if you have Barometric Aiding
How many Satellites are needed for RAIM to be able to isolate a corrupted signal?
- 6 Sats
- 5 Sats, If you have Barometric Aiding
Does our aircraft have DME?
No, we have GPS in lieu of DME
What restrictions are placed on our use of GPS in lieu of DME?
- GPS database must be current
- Must have at least Enroute RAIM capability
- Procedures must be established for RAIM outages (delays, cancelations)
- CDI must be set to terminal sensitivity (1 NM) when tracking GPS course in the terminal area.
- Your alternate airport, if required, must have a non-GPS approach available (Cannot require DME)
When should Approach Mode be ARMED when using GPS and why?
- When within 30 NM of the airport
- This is to ensure that the automatic CDI sensitivity change occurs from Enroute (+- 2 NM) to Terminal (+- 1 NM).
On a GPS approach, what are the following CDI sensitivity changes:
- Enroute
- Approach
- Final
Enroute
+- 2 NM (with RAIM, 5nm without)
Approach
+- 1 NM, within 30 NM of the airport
Final
+- 0.3 NM, when within 2 NM of the FAF
What happens when Approach Mode is NOT activate prior to at least 2 NM from the FAF? (3 things)
- Approach Mode will not automatically activate
- Sensitivity will not drop to Approach levels of +- 0.3 NM
- You should execute the missed approach.
What are the 3 Main segments of the satellite based navigation systems?
- Space segment - Satellites
- Control segment - Ground stations which increase accuracy
- User segment - GPS Receivers
What is the difference between PBN, RNAV, and RNP?
- PBN is the broad concept related to any kind of navigating based on performance metrics VS the old way of navigating with radio ground facilities. PBN requires its specified accuracy to be maintained 95% of the time.
(EXAMPLES: IRS, DME-RNAV) - RNAV, and RNP are under the umbrella of PBN
- RNAV (Area Navigation) is a system that uses GPS accurate to within specified tolerances to navigate point to point, along waypoints. An IRS/INS system is an example of this, along with Non-WAAS/RAIM GPS systems (basic GPS)
- RNP (Required Navigation Performance) is a special type of PBN requiring two things.
- Guarantee accuracy 95% of the time
- Have the capability to alert the crew if accuracy
cannot be verified. (RAIM/WAAS)
What special equipment is needed to perform an LPV approach?
GPS equipment must have WAAS and it must be functional
What is the difference between RNP and RNAV?
The main difference is that RNAV could be any kind of approved point to point navigation system
While…
RNP requires specific equipment like WAAS and RAIM to ensure accuracy and has crew alerting capabilities
What is the accuracy of a WAAS enable GPS during the different IFR flight phases?
Departure = +- 0.3NM (full scale deflection)
Enoute (domestic) = +- 2NM (5NM without WAAS)
Terminal = +- 1NM
**Approach = +- 350ft at the FAF (for LPV, L/VNAV only, otherwise it will go to +- 0.3NM)
Missed = +- 0.3 NM
What enables the GPS to go down to the 350ft (700ft total width) full deflection accuracy in the approach environment?
WAAS.
- This enables us to perform ILS ‘like’ LPV approaches
- Without WAAS, the accuracy will not step down, and we cannot fly down to LPV mins.
Which type of RNAV/RNP mins require WAAS to be functional?
LPV & LP mins
When does the GPS auto switch to Departure CDI Scaling (+- 0.3NM)?
It switches to Departure once a DP is activated in the FMS
When does the GPS auto switch from Enroute CDI scaling (+-2 NM) to Terminal scaling (+- 1NM)?
When within 31 NM of the arrival airport
You see RNP AR or (RNP) in the title of an IAP, what does this mean?
Special RNP authorization is required for the Aircraft, Crew, and Operation.
** We are do not have any of these Authorization so we cant fly these approaches
What is an LPV approach?
Localizer Performance with Vertical Guidance
- Its an APV (approach with vertical guidance)
- Mimics ILS performance with GPS
- Lowest minimums
- Requires WAAS
What is an LNAV/VNAV approach and what equipment is required?
An approach with Lateral Navigation and Vertical Navigation
- Vertical Navigation is provided by Baro-Aided VNAV
- Raim + Baro-Aiding is required
Does the G1000 have Baro-VNAV?
No, we do not
- Therefore we cannot fly LVAV/VNAV if we lose WAAS
What is Baro-VNAV?
The FMS computer uses combines information from the following sources to compute a GS
1. Lateral guidance of the
2. Altitude derived from the Static instruments
3. Data from the IAPs in the database
What is an LP approach and what is needed to fly it?
Localizer Performance approach
- Mimics the performance of a localizer approach
- WAAS is required
What equipment is required to fly a LPV approach?
TSO-146 WAAS capable GPS
What equipment is required for an LP approach?
TSO-146 WAAS capable GPS
What does the fail down tree look like for RNAV/RNP approaches?
1.LPV
2. LNAV/VNAV (if Baro-VNAV equipped)
3. LNAV
———————————-
1. LP
2. LNAV
How will you know if you have lost WAAS capability in the G1000 on the approach?
- The HSI GPS indications will change from a purple LPV, to a yellow LNAV.
- IF this happens prior to the FAF, you will also get a white Alert message
What will happen and what should you do if you lose WAAS on an IAP before the FAF?
You will see..
1. The purple LPV HSI indication will change to a yellow LNAV
2. You will get a White Alert message stating the the IAP has been downgraded
You must do…
1. Use the Time/Ref button to switch to the higher minima
2. Remember to switch to NON-Precision callouts
3. Bug the new mins