ADX Navigation and Route Planning 2 — Questions and Answers
Question 1: When planning a route over mountainous terrain, what minimum enroute altitude (MEA) consideration is MOST critical for a dispatcher?
- Terrain clearance of 1,000 feet in non-mountainous areas and 2,000 feet in designated mountainous areas (Correct answer)
- A flat 2,000-foot clearance above all terrain regardless of location
- Clearance based solely on the aircraft's service ceiling
- MEA is only applicable to IFR operations above FL180
Correct answer: Terrain clearance of 1,000 feet in non-mountainous areas and 2,000 feet in designated mountainous areas
FAA regulations require 1,000 feet of obstacle clearance in non-mountainous areas and 2,000 feet in designated mountainous areas for IFR enroute operations.
Question 2: What does the term 'OROCA' stand for and how is it used in route planning?
- Off-Route Obstacle Clearance Altitude; provides 1,000/2,000 ft obstacle clearance in off-airway areas (Correct answer)
- Overwater Route Oceanic Clearance Altitude; used for oceanic planning only
- Official Route Obstacle Clearance Altitude; replaces MEA on all routes
- Off-Route Oceanic Clearance Altitude; used for ETOPS planning
Correct answer: Off-Route Obstacle Clearance Altitude; provides 1,000/2,000 ft obstacle clearance in off-airway areas
OROCA (Off-Route Obstacle Clearance Altitude) provides the same 1,000/2,000 ft obstacle clearance as MEA but applies to off-airway off-route areas.
Question 3: A flight is planned from Chicago O'Hare (ORD) to Denver International (DEN). The dispatcher notes a SIGMET for severe turbulence along the direct route. What is the BEST initial course of action?
- Evaluate an alternate route that avoids the SIGMET area and assess fuel implications (Correct answer)
- Cancel the flight until the SIGMET expires
- File the original route and let the crew decide in flight
- Ignore the SIGMET if the aircraft is above FL300
Correct answer: Evaluate an alternate route that avoids the SIGMET area and assess fuel implications
Dispatchers have joint responsibility for flight safety and must proactively evaluate alternate routing to avoid significant hazards like severe turbulence SIGMETs.
Question 4: What is the primary purpose of a Standard Instrument Departure (SID) in route planning?
- To provide a standardized, obstacle-cleared departure path from an airport to the enroute structure (Correct answer)
- To reduce fuel burn during the climb phase only
- To assign ATC priority to heavy aircraft during departure
- To specify the cruise altitude for the first segment of flight
Correct answer: To provide a standardized, obstacle-cleared departure path from an airport to the enroute structure
SIDs provide a standardized, obstacle-cleared transition from the departure airport to the enroute airway structure, simplifying ATC clearances.
Question 5: When calculating true course on a sectional chart, a dispatcher measures the course as 275°. The variation in the area is 10°E. What is the magnetic course?
- 265° (Correct answer)
- 285°
- 275°
- 255°
Correct answer: 265°
Magnetic course = True course − East variation (or + West variation); 275° − 10°E = 265° magnetic.
Question 6: What is the significance of the Maximum Authorized Altitude (MAA) on a jet route?
- It is the highest altitude at which a route is usable, above which ATC cannot guarantee separation or navigation signal reception (Correct answer)
- It is the maximum altitude an aircraft type is certified to fly
- It is the upper limit of Class A airspace
- It marks the boundary between RVSM and non-RVSM airspace
Correct answer: It is the highest altitude at which a route is usable, above which ATC cannot guarantee separation or navigation signal reception
The MAA is the highest usable altitude on a route; above it, navigation signal coverage or ATC separation may not be guaranteed.
Question 7: During route planning, a dispatcher identifies that a waypoint is listed as 'RNAV only' on the planned route. Which navigation requirement does this impose?
- The aircraft must be RNAV-equipped and the crew must be trained and authorized for RNAV operations (Correct answer)
- The route requires GPS only and no other navigation aids
- RNAV waypoints are optional and may be bypassed without a notation
- The aircraft must carry dual INS systems for all RNAV waypoints
Correct answer: The aircraft must be RNAV-equipped and the crew must be trained and authorized for RNAV operations
RNAV-only waypoints require the aircraft to be properly equipped and the operator to have RNAV authorization; traditional ground-based nav alone is insufficient.
ADX Navigation and Route Planning 2
When planning a route over mountainous terrain, what minimum enroute altitude (MEA) consideration is MOST critical for a dispatcher?