NAV Flashcards
Describe VOR navigation.
VOR (VHF Omni Range) is a ground-based navigation technology in which stations or navaids transmit signals identifiable with aircraft receiver equipment for each radial of compass degree direction from the station, oriented to magnetic north. An aircraft may navigate directly TO or FROM a particular station within its range, known as service volume.
The greatest distance a VOR signal may be received when within ___________ altitude range
A high class or high altitude VOR signal may be received as much as 130 nautical miles from the station within FL180 to FL450. Two VOR stations may be as much as 260 nautical miles apart, and an aircraft navigated FROM a station up to 130 nm away, then TO the next station up to 130 nm away. VOR navigation is highly accurate (1-2°) but requires that the receiver be within the line-of-site of the navaid. An audible Morse code identifier may be heard through the receiver to enable positive identification of the navaid being received.
Describe DME
Distance Measuring Equipment (DME) is a signal available from many VOR navaids which may be received by a DME receiver onboard an aircraft, and indicates distance from or to a VOR navaid so equipped. A DME signal may be received close to 200 nautical miles from the transmitter. A DME receiver is required if using VOR navigation at any altitude.
What is a VORTAC?
A VORTAC is a location where a civilian VOR navaid is co-located with a military TACAN navaid. A TACAN navaid transmits a DME signal civilian aircraft equipment can receive.
What is NDB?
A nondirectional beacon (NDB) is a ground-based navaid which transmits a signal in all directions. Aircraft equipment capable of receiving an NDB signal is known as an automatic direction finder (ADF). Unlike a VOR, an NDB doesn’t transmit a signal which indicates a specific compass degree radial, rather a more generalized signal in which an ADF display will point to the navaid. If the pilot steers the aircraft such that the ADF display pointer coincides with the aircraft direction, the aircraft will eventually arrive (fly over) the navaid. NDB signal reception does not require line-of-site between the navaid and receiver, Precipitation static and thunderstorms can cause erroneous ADF indications, as the receiver may be inaccurate or point to the source of the static in the atmosphere.
What is GPS or GNSS?
GNSS stands for Global Navigation Satellite System and GPS stands for Global Positioning System. GNSS refers to a space-based navigation system. GPS refers to a GNSS operated and maintained by the US Department of Defense (DOD).
GNSS or GPS is a space-based time transfer system of navigation. An aircraft receiver receives signals simultaneously from several satellites to determine the aircraft position.
A signal from a minimum of three satellites must be received for basic location and navigation information, and a minimum of five for altitude accuracy when used for an instrument approach with vertical guidance. Receiver Autonomous Integrity Monitoring (RAIM) is a receiver indication that signals from five satellites are being received.
What is RNAV?
RNAV stands for Area Navigation. An aircraft RNAV navigation system uses as many VOR and/or DME signals to permit the pilot to navigate on any desired, direct course, rather than to have to navigate directly TO or FROM a VOR navaid.
RNAV also refers to use of GNSS/GPS navigation technology since it permits navigation on a direct course.
What is INS or IRS?
An Inertial Navigation System (INS) or Inertial Reference System (IRS) is onboard navigation technology which can receive external signals from navigation sources, but does not require reception to provide aircraft position and course guidance. INS/IRS technology is a self-contained navigation system. Such aircraft equipment uses gyros and accelerometers to determine the aircraft location and provide course navigation guidance in the absence of navigation signals in areas where it is unavailable or not reliable.
What is a Flight Management System or FMS?
A Flight Management System (FMS) is onboard aircraft navigation equipment which consolidates all navigation signals and information. An FMS contains a database of all ground navaids, published airways, and RNAV waypoints. All consolidated information is used to display course guidance.
What is an ILS?
An instrument landing system (ILS) is a ground-based navigation system in which signals received by onboard aircraft equipment provides lateral guidance to the runway center line and vertical guidance to the touchdown zone of the runway when the appropriate frequency is selected with aircraft receiver equipment.
Main components of an ILS
1.Guidance (localizer for lateral, glide slope for vertical)
2.Range (marker beacons and/or DME)
3.Visual (approach lights, precision approach path indicator/PAPI, Runway End Identifier Lights, touchdown zone lights, runway threshold lights, runway centerline lights, medium or high intensity runway lights)
Precision instrument approach versus a nonprecision approach
A precision instrument approach has operational vertical guidance (glide slope). A fully functional ILS is an example of a precision approach. Any instrument approach in which a ground-based glide slope is not available is considered a nonprecision approach. VOR, LOC, LDA, and SDF are examples of nonprecision approaches. A GPS approach may provide vertical guidance but is not considered a glide slope so therefore is considered an instrument approach with vertical guidance rather than a precision approach.
What is a Decision Height (DH)?
A Decision Height (DH) is a published height above ground level at which a descent on an ILS may not continue unless the pilot has visually acquired at least one of the following visual cues:
Approach lights*
Precision Approach Path Indicator (PAPI)
Runway pavement, lights or markings
*Approach lights may only be used alone to no lower than 100’ AGL, unless red side row bars or red terminating lights are visible.
Decision Altitude (DA) is the published minimum altitude expressed above sea level (MSL)
What is Minimum Descent Height (MDH)?
Minimum Descent Height (MDH) is a published minimum height above ground at which a descent on a nonprecision instrument approach may not continue unless the pilot has visually acquired at least one of the following visual cues:
Approach lights*
Precision Approach Path Indicator (PAPI)
Runway pavement, lights or markings
*Approach lights may only be used alone to no lower than 100’ AGL, unless red side row bars or red terminating lights are visible. Minimum Descent Altitude (MDA) is the published minimum altitude expressed above sea level (MSL)
What are typical approach minimums for a Cat I ILS?
200’ DH 1/2SM (2400 RVR) or 1800 RVR if touchdown zone lights or centerline lights are installed and operational
