ATPL Navigation & Flight Planning Questions

An aircraft is flying directly over a DME ground station at FL360. What will the DME display read?

• Approximately 6 nm, reflecting slant range rather than ground distance
• Zero, since DME always reads ground distance
• 36 nm, matching the flight level number
• A blank or invalid reading, since DME cannot function directly overhead a station

Explanation: DME measures slant range - the direct line-of-sight distance to the station - not ground distance. Directly overhead a station at FL360 (roughly 36,000 ft, or about 6 nm of altitude), the DME will read approximately 6 nm rather than zero, since altitude itself contributes to that slant-range distance.

Navigation - Radio Navigation Aids (DME)

Where would a pilot expect to find the dates and times during which a temporary danger area is active?

• NOTAMs and the AIP (Aeronautical Information Publication)
• SIGMETs only
• Radio navigation (RAD/NAV) charts only
• METARs for the nearest aerodrome

Explanation: Temporary danger area activation details are published through NOTAMs and the AIP, which are the standard channels for aeronautical information about airspace status - not SIGMETs (which cover hazardous weather) or routine weather reports.

Navigation - Flight Planning Information Sources

In standard fuel-planning terminology, 'final reserve fuel' is generally intended to cover:

• A minimum amount of holding fuel at low altitude over the destination (or alternate) to be used only in genuine emergency circumstances
• The fuel used taxiing from the gate to the runway before takeoff
• Fuel to cover an additional planned enroute diversion
• Fuel added purely at the captain's discretion with no defined minimum

Explanation: Final reserve fuel is a minimum protected quantity - commonly expressed as a period of holding at a low altitude over the destination or alternate - that is not meant to be used in normal operations, distinct from contingency fuel (covering enroute uncertainties) and alternate fuel (covering the flight to a designated alternate).

Navigation - Fuel Planning & Reserves

What is the 'cone of confusion' associated with a VOR station?

• An area more or less directly above the station where bearing indications become erratic and unreliable due to the signal geometry there
• A permanently unusable sector of the VOR's service volume at low altitude
• An area where the VOR signal is jammed by nearby DME stations
• A region found only around NDB stations, never VOR stations

Explanation: Almost directly overhead a VOR station, the geometry of the transmitted signal breaks down, and bearing indications can become erratic or unreliable for a short period - a well-known and expected effect (the 'cone of confusion') rather than a fault, and it passes quickly once clear of the immediate overhead area.

Navigation - Radio Navigation Aids (VOR)

A pilot who has filed a flight plan is generally expected to do what upon safely arriving at the destination?

• Close the flight plan, so that search and rescue action is not triggered unnecessarily
• Nothing further is required once the aircraft has landed
• Refile an identical flight plan for the return leg before leaving the aircraft
• Contact only the departure aerodrome, never the destination facility

Explanation: Closing a filed flight plan on arrival (by radio, phone, or other approved means) confirms the flight completed safely - if a flight plan isn't closed within an expected window, search and rescue action can be triggered based on the assumption the flight may be overdue or missing.

Navigation - Flight Plan Closure

What is the general purpose of a pre-flight 'RAIM prediction' for a GNSS-based flight or approach?

• To check in advance whether satellite geometry is expected to provide sufficient integrity monitoring capability for the planned flight or approach
• To predict the aircraft's expected fuel burn for the flight
• To forecast weather conditions specific to the destination aerodrome
• To determine the expected wind correction angle for the route

Explanation: A RAIM prediction is a planning check, done before the flight, to assess whether the expected satellite geometry at the relevant time and location will be sufficient to support the receiver's integrity-monitoring function for the intended operation - particularly relevant for a GNSS approach where a RAIM outage would mean the approach isn't available as planned.

Navigation - GNSS Integrity Monitoring

What is 'convergency' between two meridians of longitude?

• The change of direction experienced when travelling along a great circle track (other than a meridian or the equator) as a result of meridians converging toward the poles
• The distance between two meridians measured along the equator
• A term describing two aircraft converging on the same point at the same time
• The angle between a compass needle and the aircraft's nose

Explanation: Because meridians of longitude are not parallel but converge toward the poles, a great circle track (other than one running along a meridian or the equator) continuously changes its true direction as it is followed - this change of direction between two points, resulting from meridian convergence, is called convergency, and it is zero at the equator and greatest near the poles.

Navigation - Convergency

Still on the same SID chart, what altitude and radial (to the ZOL VOR) apply at waypoint TARLO?

• A030 - R283
• A040 - R210
• A030 - R103
• A050 - R193

Explanation: TARLO is charted as A040 (a crossing restriction of 4000 ft) on the R210 radial from ZOL, both read directly off the label at that waypoint -- the other options mix in radials and altitudes that belong nowhere on this chart.

Flight Planning - Departure (SID) Charts