Avionics Multiple Choice Questions on “Satellite Landing System”.
1. Which of the following is not a reason for not using the basic GPS for landing systems?
a) Accuracy
b) Integrity
c) Availability of satellites
d) Number of users
Answer: d
Clarification: The primary reason for not using basic GPS for landing systems is because does not provide the accuracy that is required for landing, it lacks a monitoring system and the availability of a sufficient number of satellites to provide location information.
2. Which of the following is supplemented with GPS to provide non-precision and Category I approaches?
a) Primary radar
b) WAAS
c) ILS
d) MLS
Answer: b
Clarification: For non-precision and Category I precision approaches, the limitations by the GPS is mitigated by the FAA’s Wide Area Augmentation System. It may be supplemented with local differential GPS stations located near runways.
3. Which of the following is not true with respect to WAAS?
a) Provides WADGPS corrections
b) Uses ground integrity broadcast
c) Provide precision approaches for Category III C
d) Provide GPS ranging function
Answer: c
Clarification: WAAS addresses the limitations by providing Wide area differential GPS error correction, a ground integrity broadcast, and a GPS ranging function from three or four geostationary satellites providing additional availability.
4. Which of the following is required to support Category II and III with DGPS?
a) High- integrity ground to air data link
b) ILS system
c) Transponder
d) DME station
Answer: a
Clarification: To support Category II and III landing operations, the additional requirement for accuracy and monitor-response times can be achieved with a differential GPD reference station and a high-integrity ground to air data link located near the runway.
5. Which of the following errors are not rectified by LDGPS?
a) Satellite ephemerides
b) Ionosphere propagation effects
c) Multi-path signal interference
d) Clock offset
Answer: c
Clarification: LDGPS operation leads to the nearly complete cancellation of errors due to satellite ephemerides, clock offset, selective availability, and ionospheric propagation, leaving mainly those errors due to multipath signal interference and receiver noise.
6. The DME station can supply integrity warnings.
a) True
b) False
Answer: b
Clarification: The runway reference station can supply integrity warnings within the required response time of 1 to 2 sec. These are located near the runway.
7. The accuracy of the SPS code solution is satisfactory for precision approaches.
a) True
b) False
Answer: b
Clarification: GPS receivers were capable of about ten solutions per second, which is sufficient for coupled flight. The accuracy of the SPS code solution without augmentation is satisfactory for nonprecision approaches.
8. The pilot has no other option than to use FLOLS to land the aircraft.
a) True
b) False
Answer: b
Clarification: The pilot has the option of coupling the autopilot to the ACLS, flying the aircraft from “needles” controlled by ACLS data, or being talked down by a shipboard controller. A manual carrier landing with ACLS resembles a land based ground controlled approach.