TACAN (Tactical Air Navigation): How It Works, Indications, & Limitations

Tactical Air Navigation

Introduction to Tactical Air Navigation

Tactical Air Navigation (TACAN) was developed to provide precise geographical navigation for military use
Like a VOR, provides 360 radials coming from the station
VOR and TACAN systems collocated are called VORTACs
An additional advantage is that TACAN ground equipment is compact and relatively easy to transport
IDs every 35 seconds
The OFF position will disconnect the unit from the aircraft power supply
STBY will receive magnetic bearing information only from ground TACAN navigation facilities
In the T/R position, the TACAN receives magnetic bearing and distance information
Cannot be used to transmit and receive voice
Will identify itself with a Morse code identifier about every 37.5/32 seconds
Transmitted one time for each 3 or 4 times that a VOR signal is transmitted when identifying a VORTAC (Very High Frequency Omnidirectional Range/Tactical Air Navigation)
Test your understanding of Tactical Air Navigation by completing the knowledge quiz, applying your knowledge in the interactive scenario, comparing your performance against the applicable Airman Certification Standards, and concluding with the topic summary to reinforce the key concepts before moving on to the next lesson.

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Tactical Air Navigation

Tactical Air Navigation Key Highlights

Tactical Air Navigation (TACAN) is a military navigation system that provides azimuth and distance information to equipped aircraft.
TACAN combines bearing and distance measuring capabilities into a single navigation aid for military aviation operations.
Civilian aircraft equipped with DME can use the distance component of many TACAN stations.
VORTAC facilities combine VOR and TACAN systems to provide navigation services for both civilian and military aircraft.
TACAN systems operate in the ultra-high frequency (UHF) radio spectrum and provide accurate navigation information.
Pilots use TACAN and VORTAC facilities for en route navigation, terminal operations, and instrument approach procedures.
Distance information from TACAN stations is displayed similarly to conventional DME equipment.
Navigation accuracy depends on proper equipment operation, station identification, and signal reception quality.
Modern satellite-based navigation systems have reduced reliance on TACAN navigation in some operational environments.
Understanding TACAN operation improves navigation proficiency, military-civil coordination awareness, and overall flight safety.

Tactical Air Navigation

Tactical Air Navigation History

For reasons peculiar to military or naval operations (unusual siting conditions, the pitching and rolling of a naval vessel, etc.) the civil VOR/Distance Measuring Equipment (DME) system of air navigation was considered unsuitable for military or naval use
A new navigational system, TACAN, was therefore developed by the military and naval forces to more readily lend itself to military and naval requirements
As a result, the FAA has integrated TACAN facilities with the civil VOR/DME program
Although the theoretical, or technical principles of operation of TACAN equipment are quite different from those of VOR/DME facilities, the end result, as far as the navigating pilot is concerned, is the same
These integrated facilities are called VORTACs

Tactical Air Navigation

Tactical Air Navigation Components

TACAN ground equipment consists of either a fixed or mobile transmitting unit
The airborne unit in conjunction with the ground unit reduces the transmitted signal to a visual presentation of both azimuth and distance information
TACAN is a pulse system and operates in the Ultrahigh Frequency (UHF) band of frequencies
Its use requires TACAN airborne equipment and does not operate through conventional VOR equipment

Tactical Air Navigation

Station Passage

DME decreases to minimum
Needle rotates 180°
CDI (Course Deviation Indicator) oscillates from side to side
TO/FROM indicator switches from TO to FROM

Note: Instrument indications will fluctuate when close to the station; this does not necessarily mean your aircraft is off course. Do not chase the needle when close to the station. Limit heading corrections for drift when close to avoid overshooting

Tactical Air Navigation

Frequencies

TACAN operates in the UHF (1000 megahertz (MHz)) band with 126 two-way channels in the operational mode (X or Y) for 252 total
Air-to-ground DME frequencies are in the 1025 to 1150 MHz range
Ground-to-air frequencies are in the 962 to 1213 MHz range

Tactical Air Navigation

Ground Equipment

Consists of a rotating type antenna transmitting bearing and a receiver-transmitter (transponder) for transmitting distance information
Ground stations are usually dual transmitter equipped
One operational and the other standby
Sometimes TACAN reception might be suspected of being in error or bearing/distance unlock conditions may be encountered in flight

Tactical Air Navigation

Distance Measuring Equipment (DME)

The aircraft sends an interrogation to the ground station and the station sends a reply back
The elapsed time between transmission and reception is the distance in nautical miles (NM)
The pulses require about 12 microseconds round trip travel time per NM of distance
Replies are random to ensure other aircraft using the same station get a unique signal
If the signals are interrupted, a memory circuit maintains the last distance indication for 10 seconds
After 10 seconds, a search function begins to lock back onto the station, taking up to 22 seconds
Furnishes reliable, line of sight, slant range information at distances up to 199 NM with an accuracy of 2 mile or 3% of the distance, whichever is greater

Tactical Air Navigation

TACAN Limitations

Cannot transmit voice
DME equipment is an integral part in providing slant range up to 399.9 NM with an accuracy of 2 miles or 3% of the distance, whichever is greater
Cone of confusion:
- Exists where TACAN azimuth information is not available
- The "cone" varies from 60° to 110° wide
- TACAN DME and ID signal will be received and station passage will be noted by minimum DME
- Although narrow at low altitudes, this "cone" expands to about 18 NM across at 30,000'
- Because of the size of TACAN cone of confusion, holding on a TACAN will always be established using DME
TACAN azimuth Standard Service Volumes are T, L, or H; the DME component may have a different classification:
- The SSV (Standard Service Volume) defines protected signal reception for off-route navigation, but does not protect against blockage by terrain or obstructions.
- Reception may be possible beyond the ranges, however interference from other stations on the same frequencies may cause 40° off bearing lock-on
40° off bearing TACAN pointer lock-on error:
- Locking on to multiples of 40° from the desired radial due to inherent operating functions of the older crystal controlled receivers
- Solid-state electronics in the T-45C should preclude this problem from occurring
- Re-channeling the receiver and tuning back to the original station may remedy the error
Failure to lock on:
- Misalignment of equipment
- Worn aircraft control box
- Re-channeling the receiver and tuning from the opposite direction back to the original station may remedy the error
Co-channel interference:
- Receiving signals (DME, azimuth, identifier) from more than one TACAN station due to the relationship between aircraft's high altitude and station locations

Tactical Air Navigation

NAVAID Identifier Removal During Maintenance

During periods of routine or emergency maintenance, coded identification (or code and voice, where applicable) is removed from certain FAA NAVAIDs (Navigational Aids).
- During periods of maintenance VHF (Very High Frequency) ranges may radiate a T-E-S-T code [- (dot) (dot-dot-dot) -].
Removal of identification serves as a warning to pilots that the facility is officially off the air for tune-up or repair and may be unreliable even though intermittent or constant signals are received
DO NOT attempt to fly a procedure that is NOTAM (Notice to Airmen)'d out of service even if the identification is present.
- In certain cases, the identification may be transmitted for short periods as part of the testing.

Tactical Air Navigation

Tactical Air Navigation Interactive Scenario

Tactical Air Navigation

Tactical Air Navigation Knowledge Check

Choose the knowledge check that matches your current training for Tactical Air Navigation.

Why Take a Quiz?

Quizzes reinforce key concepts, identify knowledge gaps, and build confidence for real-world decisions. Quiz material is representative of the information provided here and is not based on or sourced from the Federal Aviation Administration test bank.

Tactical Air Navigation

Tactical Air Navigation-Related Airman Certification Standards

Private Pilot (Airplane) Radio Communications, Navigation Systems/Facilities, and Radar Services Airman Certification Standards

Objective: To determine that the applicant exhibits satisfactory knowledge, risk management, and skills associated with radio communications, navigation systems/facilities, and radar services available for use during flight solely by reference to instruments
References: FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-15, FAA-H-8083-25 (Pilot Handbook of Aeronautical Knowledge)
Private Pilot (Airplane) Radio Communications, Navigation Systems/Facilities, and Radar Services Lesson Plan.

Knowledge 3 ACS Elements

PA.VIII.F.K1:
Operating communications equipment to include identifying and selecting radio frequencies, requesting and following air traffic control (ATC) instructions.
PA.VIII.F.K2:
Operating navigation equipment to include functions and displays, and following bearings, radials, or courses.
PA.VIII.F.K3:
Air traffic control facilities and services.

Risk Management 2 ACS Elements

Skills 3 ACS Elements

PA.VIII.F.S1:
Maintain airplane control while selecting proper communications frequencies, identifying the appropriate facility, and managing navigation equipment.
PA.VIII.F.S2:
Comply with ATC instructions.
PA.VIII.F.S3:
[Archived].

Private Pilot (Airplane) Navigation Systems and Radar Services Airman Certification Standards

Objective: To determine whether the applicant exhibits satisfactory knowledge, risk management, and skills associated with navigation systems and radar services.
References: AC 91-78; AIM; FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-25 (Pilot Handbook of Aeronautical Knowledge).
Private Pilot (Airplane) Navigation Systems and Radar Services Lesson Plan.

Knowledge 4 ACS Elements

PA.VI.B.K1:
Ground-based navigation (identification, orientation, course determination, equipment, tests, regulations, interference, appropriate use of navigation data, and signal integrity).
PA.VI.B.K2:
Satellite-based navigation (e.g., equipment, regulations, authorized use of databases, and Receiver Autonomous Integrity Monitoring (RAIM)).
PA.VI.B.K3:
Radar assistance to visual flight rules (VFR) aircraft (e.g., operations, equipment, available services, traffic advisories).
PA.VI.B.K4:
Transponder (Mode(s) A, C, and S) and Automatic Dependent Surveillance-Broadcast (ADS-B).

Risk Management 5 ACS Elements

PA.VI.B.R1:
Management of automated navigation and autoflight systems.
PA.VI.B.R2:
Distractions, task prioritization, loss of situational awareness, or disorientation.
PA.VI.B.R3:
Limitations of the navigation system in use.
PA.VI.B.R4:
Loss of a navigation signal.
PA.VI.B.R5:
Use of an electronic flight bag (EFB), if used.

Skills 7 ACS Elements

PA.VI.B.S1:
Use an airborne electronic navigation system.
PA.VI.B.S2:
Determine the airplane's position using the navigation system.
PA.VI.B.S3:
Intercept and track a given course, radial, or bearing.
PA.VI.B.S4:
Recognize and describe the indication of station or waypoint passage.
PA.VI.B.S5:
Recognize signal loss or interference and take appropriate action, if applicable.
PA.VI.B.S6:
Use proper communication procedures when utilizing radar services.
PA.VI.B.S7:
Maintain the selected altitude ±200 feet and heading ±15°.

Commercial Pilot (Airplane) Navigation Systems and Radar Services Airman Certification Standards

Objective: To determine whether the applicant exhibits satisfactory knowledge, risk management, and skills associated with navigation systems and radar services.
References: AC 91-78; AIM; FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-25 (Pilot Handbook of Aeronautical Knowledge).
Commercial Pilot (Airplane) Navigation Systems and Radar Services Lesson Plan.

Knowledge 4 ACS Elements

CA.VI.B.K1:
Ground-based navigation (identification, orientation, course determination, equipment, tests, regulations, interference, appropriate use of navigation data, and signal integrity).
CA.VI.B.K2:
Satellite-based navigation (e.g., equipment, regulations, authorized use of databases, and Receiver Autonomous Integrity Monitoring (RAIM)).
CA.VI.B.K3:
Radar assistance to visual flight rules (VFR) aircraft (e.g., operations, equipment, available services, traffic advisories).
CA.VI.B.K4:
Transponder (Mode(s) A, C, and S) and Automatic Dependent Surveillance-Broadcast (ADS-B).

Risk Management 5 ACS Elements

CA.VI.B.R1:
Management of automated navigation and autoflight systems.
CA.VI.B.R2:
Distractions, task prioritization, loss of situational awareness, or disorientation.
CA.VI.B.R3:
Limitations of the navigation system in use.
CA.VI.B.R4:
Loss of a navigation signal.
CA.VI.B.R5:
Use of an electronic flight bag (EFB), if used.

Skills 7 ACS Elements

CA.VI.B.S1:
Use an airborne electronic navigation system.
CA.VI.B.S2:
Determine the airplane's position using the navigation system.
CA.VI.B.S3:
Intercept and track a given course, radial, or bearing.
CA.VI.B.S4:
Recognize and describe the indication of station or waypoint passage.
CA.VI.B.S5:
Recognize signal loss or interference and take appropriate action, if applicable.
CA.VI.B.S6:
Use proper communication procedures when utilizing radar services.
CA.VI.B.S7:
Maintain the selected altitude ±100 feet and heading ±10°.

Private Pilot (Helicopter) Navigation Systems and Radar Services Airman Certification Standards

Area of Operation VII: Navigation.
Task B: Navigation Systems and Radar Services.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with navigation systems and radar services.
Note: The evaluator should reference the manufacturer's equipment supplement(s) as necessary for appropriate limitations, procedures, etc.
References: AC 91-78; AIM; FAA-H-8083-2, FAA-H-8083-21, FAA-H-8083-25
Private Pilot (Helicopter) Navigation Systems and Radar Services Lesson Plan.

Knowledge 4 ACS Elements

PH.VII.B.K1:
Ground-based navigation (identification, orientation, course determination, equipment, tests, regulations, interference, appropriate use of navigation data, and signal integrity).
PH.VII.B.K2:
Satellite-based navigation (e.g., equipment, regulations, authorized use of databases, and Receiver Autonomous Integrity Monitoring (RAIM)).
PH.VII.B.K3:
Radar assistance to visual flight rules (VFR) aircraft (e.g., operations, equipment, available services, traffic advisories).
PH.VII.B.K4:
Transponder (Mode(s) A, C, and S) and Automatic Dependent Surveillance-Broadcast (ADS-B).

Risk Management 5 ACS Elements

PH.VII.B.R1:
Management of automated navigation and autoflight systems.
PH.VII.B.R2:
Distractions, task prioritization, loss of situational awareness, or disorientation.
PH.VII.B.R3:
Limitations of the navigation system in use.
PH.VII.B.R4:
Loss of a navigation signal.
PH.VII.B.R5:
Use of an electronic flight bag (EFB), if used.

Skills 7 ACS Elements

PH.VII.B.S1:
Use an airborne electronic navigation system.
PH.VII.B.S2:
Determine the aircraft's position using the navigation system.
PH.VII.B.S3:
Intercept and track a given course, radial, or bearing.
PH.VII.B.S4:
Recognize and describe the indication of station or waypoint passage.
PH.VII.B.S5:
Recognize loss of navigational signal and take appropriate action.
PH.VII.B.S6:
Use proper communication procedures when utilizing radar services.
PH.VII.B.S7:
Maintain the selected altitude, ±200 feet and headings, ±15°.

Instrument Rating Aircraft Flight Instruments and Navigation Equipment Airman Certification Standards

Objective: To determine whether the applicant exhibits satisfactory knowledge, risk management, and skills associated with managing instruments appropriate for an IFR flight.
References: 14 CFR part 91; AC 90-100, AC 90-105, AC 90-107, AC 91-78, AC 91.21-1; AIM; FAA-H-8083-2 (Risk Management Handbook), FAA-H-8083-3 (Airplane Flying Handbook), FAA-H-8083-15, and FAA-H-8083-25 (Pilot's Handbook of Aeronautical Knowledge).
Instrument Rating Aircraft Flight Instruments and Navigation Equipment Lesson Plan.

Knowledge 3 ACS Elements

IR.II.B.K1:
Operation of the aircraft's applicable flight instrument system(s), including:
- IR.II.B.K1a:
  Pitot-static instrument system and associated instruments.
- IR.II.B.K1b:
  Gyroscopic/electric/vacuum instrument system and associated instruments.
- IR.II.B.K1c:
  Electrical systems, electronic flight instrument displays [primary flight display (PFD), multifunction display (MFD)], transponder, and automatic dependent surveillance-broadcast (ADS-B).
- IR.II.B.K1d:
  Magnetic compass.
IR.II.B.K2:
Operation of the aircraft's applicable navigation system(s), including:
- IR.II.B.K2a:
  Very high frequency (VHF) Omnidirectional Range (VOR), distance measuring equipment (DME), instrument landing system (ILS), and marker beacon receiver/indicators.
- IR.II.B.K2b:
  Area navigation (RNAV), global positioning system (GPS), Wide Area Augmentation System (WAAS), flight management system (FMS), and autopilot.
IR.II.B.K3:
Use of an electronic flight bag (EFB), if used.

Risk Management 5 ACS Elements

IR.II.B.R1:
Monitoring and management of automated systems.
IR.II.B.R2:
Difference between approved and non-approved navigation devices.
IR.II.B.R3:
Modes of flight and navigation instruments, including failure conditions.
IR.II.B.R4:
Use of an electronic flight bag.
IR.II.B.R5:
Use of navigation databases.

Skills 2 ACS Elements

Sport Pilot (Helicopter) Navigation Systems and Radar Services Airman Certification Standards

Area of Operation VII: Navigation.
Task B: Navigation Systems and Radar Services.
Objective: To determine the applicant exhibits satisfactory knowledge, risk management, and skills associated with navigation systems and radar services.
References: AC 91-78; AIM; FAA-H-8083-2, FAA-H-8083-21, FAA-H-8083-25
Sport Pilot (Helicopter) Navigation Systems and Radar Services Lesson Plan.

Knowledge 4 ACS Elements

SH.VII.B.K1:
Ground-based navigation (identification, orientation, course determination, equipment, tests, regulations, interference, appropriate use of navigation data, and signal integrity).
SH.VII.B.K2:
Satellite-based navigation (e.g., equipment, regulations, authorized use of databases, and Receiver Autonomous Integrity Monitoring (RAIM)).
SH.VII.B.K3:
Radar assistance to visual flight rules (VFR) aircraft (e.g., operations, equipment, available services, traffic advisories).
SH.VII.B.K4:
Transponder (Mode(s) A, C, and S) and Automatic Dependent Surveillance-Broadcast (ADS-B).

Risk Management 5 ACS Elements

SH.VII.B.R1:
Management of automated navigation and autoflight systems.
SH.VII.B.R2:
Distractions, task prioritization, loss of situational awareness, or disorientation.
SH.VII.B.R3:
Limitations of the navigation system in use.
SH.VII.B.R4:
Loss of a navigation signal.
SH.VII.B.R5:
Use of an electronic flight bag (EFB), if used.

Skills 7 ACS Elements

SH.VII.B.S1:
Use an airborne electronic navigation system.
SH.VII.B.S2:
Determine the aircraft's position using the navigation system.
SH.VII.B.S3:
Intercept and track a given course, radial, or bearing.
SH.VII.B.S4:
Recognize and describe the indication of station or waypoint passage.
SH.VII.B.S5:
Recognize loss of navigational signal and take appropriate action.
SH.VII.B.S6:
Use proper communication procedures when utilizing radar services, as applicable.
SH.VII.B.S7:
Maintain the selected altitude, ±200 feet and headings, ±15°.

Tactical Air Navigation

Tactical Air Navigation Conclusion

Although designed differently, TACANs function the same as VHF Omni-Directional Range (VOR) and Distance Measuring Equipment (DME), or VORTAC
Pilots should be aware of the possibility of momentary erroneous indications on cockpit displays when the primary signal generator for a ground-based navigational transmitter is inoperative.
- Pilots should disregard any navigation indication, regardless of its apparent validity, if the particular transmitter was identified by NOTAM or otherwise as unusable or inoperative.
Remember, the FAA requests user reports on NAVAID outages.
Still looking for something? Continue searching:

Tactical Air Navigation

Tactical Air Navigation

Introduction to Tactical Air Navigation

Tactical Air Navigation Key Highlights

Tactical Air Navigation History

Tactical Air Navigation Components

Station Passage

Frequencies

Ground Equipment

Distance Measuring Equipment (DME)

TACAN Limitations

NAVAID Identifier Removal During Maintenance

Tactical Air Navigation Interactive Scenario

Interactive Scenario

Scenario Complete

Tactical Air Navigation Knowledge Check

Core Knowledge Review

Advanced Application

Why Take a Quiz?

Private Pilot (Airplane) Radio Communications, Navigation Systems/Facilities, and Radar Services Airman Certification Standards

Private Pilot (Airplane) Navigation Systems and Radar Services Airman Certification Standards

Commercial Pilot (Airplane) Navigation Systems and Radar Services Airman Certification Standards

Private Pilot (Helicopter) Navigation Systems and Radar Services Airman Certification Standards

Instrument Rating Aircraft Flight Instruments and Navigation Equipment Airman Certification Standards

Sport Pilot (Helicopter) Navigation Systems and Radar Services Airman Certification Standards

Tactical Air Navigation Conclusion

Tactical Air Navigation References