C. Daniel Prather, Ph.D., A.A.E, CAM

Mod 1
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Mod 3

Mod 3
 IFR operations in any class of controlled airspace requires a pilot to file an IFR flight plan and receive an appropriate
ATC clearance.
 Standard IFR separation is provided to all aircraft operating under IFR in controlled airspace.
 Pilots operating under VFR requirements are responsible to ensure that ATC clearance or radio communication requirements are met prior to entry into Class B, Class C, or
Class D airspace.
 Pilots retain this responsibility when receiving ATC radar advisories.

Mod 3
 Traffic advisories will be provided to all aircraft as the controller's work situation permits.
 Safety alerts , on the other hand, are mandatory services provided to all pilots and may include either a terrain/obstruction alert or an aircraft conflict/Mode C intruder alert

 Regulatory
 Class A
 Class B
 Class C
 Class D
 Class E
 Restricted areas
 Prohibited Areas
Mod 3
 Non-regulatory
 Military operations areas (MOAs)
 Warning areas
 Alert areas
 Controlled firing areas

Mod 3
 Controlled
 Uncontrolled
 Special use
 Other
 Categories & types are dictated by several factors
 The density and complexity of aircraft movements.
 The nature of operations conducted within the airspace.
 The level of safety required.
 The national and public interest will affect the category or type of airspace.

Mod 3

Mod 3
 Exists from 18,000 feet mean sea level (MSL) up to and including flight level (FL) 600, including the airspace overlying the waters within 12 nautical miles (NM) of the coast of the 48 contiguous States and Alaska; and designated international airspace beyond 12 NM of the coast of the 48 contiguous States and Alaska within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic procedures are applied.
 All aircraft in Class A airspace must operate under IFR.

Mod 3
 Class B exists from the surface to 10,000 feet MSL surrounding the nation's busiest airports in terms of IFR operations or passenger enplanements.
 An ATC clearance is required for all aircraft to operate in the area, and all aircraft that are so cleared receive separation services within the airspace.
 The cloud clearance requirement for VFR operations is "clear of clouds."
 Pilots are required to obtain an ATC clearance prior to operating in Class B airspace.
 Aircraft must be equipped with an operable two-way radio capable of communicating with ATC on appropriate frequencies for that airspace.

 Exists from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower, are serviced by a radar approach control, and that have a certain number of IFR operations or passenger enplanements.
 Usually consists of a 5 NM radius core surface area that extends from the surface up to 4,000 feet above the airport elevation, and a 10 NM radius shelf area that extends no lower than 1,200 feet up to 4,000 feet above the airport elevation.
 Although no specific pilot certification is required to operate in
Class C airspace, aircraft must be equipped with a two-way radio and (unless otherwise authorized by ATC), an operable radar beacon transponder with automatic altitude reporting equipment.
Mod 3

Mod 3
 Exists from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower.
 Although no specific pilot certification is required to operate in Class D airspace, aircraft must be equipped with a two-way radio (unless otherwise authorized by
ATC).
 No separation services are provided to VFR aircraft within Class D airspace.

 No specific pilot certification is required, nor is specific equipment.
 Various types of Class E airspace:
 Surface area designated for an airport - When designated as a surface area for an airport, the airspace will be configured to contain all instrument procedures.
 Extension to a surface area - There are Class E airspace areas that serve as extensions to Class B, Class C, and Class D surface areas designated for an airport. Such airspace provides controlled airspace to contain standard instrument approach procedures without imposing a communications requirement on pilots operating under VFR.
Mod 3
 Airspace used for transition - There are Class E airspace areas beginning at either 700 or 1,200 feet AGL used to transition to/from the terminal or en route environment.

Mod 3
 En Route Domestic Areas - There are Class E airspace areas that extend upward from a specified altitude and are en route domestic airspace areas that provide controlled airspace in those areas where there is a requirement to provide IFR en route ATC services but the Federal airway system is inadequate.
 Federal Airways - The Federal airways are Class E airspace areas and, unless otherwise specified, extend upward from 1,200 feet to, but not including, 18,000 feet MSL. The colored airways are green, red, amber, and blue. The VOR airways are classified as Domestic, Alaskan, and
Hawaiian.
 Offshore Airspace Areas - There are Class E airspace areas that extend upward from a specified altitude to, but not including, 18,000 feet MSL and are designated as offshore airspace areas. These areas provide controlled airspace beyond 12 miles from the coast of the U.S. in those areas where there is a requirement to provide IFR en route ATC services and within which the U.S. is applying domestic procedures.

 Unless designated at a lower altitude, Class E airspace begins at 14,500 feet MSL to, but not including, 18,000 feet MSL overlying: the 48 contiguous States including the waters within 12 miles from the coast of the 48 contiguous States; the District of Columbia; Alaska, including the waters within 12 miles from the coast of
Alaska, and that airspace above FL 600; excluding the western portion of the Alaska peninsula, and the airspace below 1,500 feet above the surface of the earth unless specifically so designated.
Mod 3
 There are no separation surfaces provided to VFR aircraft within Class E airspace

Mod 3
 Uncontrolled airspace includes Class G airspace. In essence, Class G airspace is that portion of airspace that has not been designated as Class A, Class B, Class
C, Class D, or Class E airspace.
 Minimum flight visibility and distance from cloud requirements for VFR flight may be found in 14 CFR
Section 91.155. IFR requirements may be found in 14
CFR Part 91.177

Mod 3
 Special use airspace is that airspace where activities must be confined because of their nature, or where limitations are imposed on aircraft operations that are not a part of those activities, or possibly both. Special use airspace areas are depicted on aeronautical charts, except for controlled firing areas. Special-use airspace includes both regulatory and nonregulatory airspace.
 Prohibited areas contain airspace of defined dimensions identified by an area on the surface of the earth within which the flight of aircraft is prohibited.
Such areas are established for security or other reasons associated with the national welfare.

Mod 3
 Restricted areas contain airspace identified by an area on the surface of the earth within which the flight of aircraft, while not wholly prohibited, is subject to restrictions.
 Activities within these areas must be confined because of their nature or limitations imposed upon aircraft operations that are not a part of those activities or both.
 Restricted areas denote the existence of unusual, often invisible, hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles.
 Penetration of restricted areas without authorization from the using or controlling agency may be extremely hazardous to the aircraft and its occupants.

Mod 3
 A warning area is airspace of defined dimensions, extending from three nautical miles outward from the coast of the U.S., that contains activity that may be hazardous to nonparticipating aircraft. The purpose of such warning areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both.

Mod 3
 Military operations areas (MOAs) consist of airspace of defined vertical and lateral limits established for the purpose of separating certain military training activities from IFR traffic.
 Whenever a MOA is being used, nonparticipating IFR traffic may be cleared through an MOA if IFR separation can be provided by
ATC. Otherwise, ATC will reroute or restrict nonparticipating IFR traffic.
 Examples of activities conducted in MOAs include, but are not limited to: air combat tactics, air intercepts, aerobatics, formation training, and low-altitude tactics.
 Pilots operating under VFR should exercise extreme caution while flying within a MOA when military activity is being conducted.
 The activity status of MOAs may change frequently.

Mod 3
 Alert areas are depicted on aeronautical charts to inform nonparticipating pilots of areas that may contain a high volume of pilot training or an unusual type of aerial activity.
 Pilots should remain alert when flying in these areas.
Pilots of participating aircraft, as well as pilots transiting the area, are equally responsible for collision avoidance.

Mod 3
 Controlled firing areas (CFAs) contain activities which, if not conducted in a controlled environment, could be hazardous to nonparticipating aircraft.
 The distinguishing feature of the CFA, as compared to other special use airspace, is that its activities are suspended immediately when spotter aircraft, radar, or ground lookout positions indicate an aircraft might be approaching the area.
 There is no need to chart CFAs since they do not cause a nonparticipating aircraft to change its flight path.

Mod 3

Mod 3
 Approach control – Located within a TRACON or ARTCC facility. Responsible for ensuring the safe transition of the aircraft into the terminal area.
 Clearance delivery - Coordinates and processes initial departure, route of flight, and final altitude information to a pilot.
 Departure control - Located within a TRACON or ARTCC facility. Responsible for ensuring the safe transition of the aircraft out of the terminal area and into enroute navigation.
 Flight data - The flight data position primarily relays flight plan and airport information to the other controller positions within the tower.

Mod 3
 Tower (or local) control - Responsibility of handling arriving and departing aircraft on the active runways and within the assigned airport airspace. Authorization to cross or access a runway requires approval by the local controller.
 Ground control - Responsibility for controlling all aircraft and vehicular activity on the airport movement areas.
 Clearance delivery
 Flight data

Mod 3
 Coordinates and manages the flow of aircraft in the non-movement ramp areas in proximity to the terminal building, including push back and aircraft gate assignment.
 Ramp control can be operated by airport personnel, or more likely, by airline personnel.
 Ground vehicle activity does not require authorization to operate in this area, with the exception that only individuals who have received training under Part
139.329 and have security authorization are allowed.

Mod 3
 A recorded message that continuously transmits airport information on a separate assigned frequency, or over the voice feature of an airport’s Very high frequency Omni-directional Range
(VOR) navigational aid or other radio transmitter.
 ATIS information is identified by a phonetic letter code and is updated hourly by the air traffic controller, or more often if conditions warrant.
 The purpose of ATIS is to eliminate the repetitive announcement of basic information made to pilots when they first contact the control tower.
 ATIS generally includes the following information: airport identifier,
UTC time, wind direction and speed, visibility, cloud ceiling, temperature and dew point, altimeter setting, instrument approaches and runways in use, NOTAMs applicable to landing, weather advisories, braking action reports, wind shear reports, construction activity, and other information.

Mod 3
 Remote Communication Air/Ground (RCAG) sites are often located at remote or non-towered airports that have frequent instrument operations, or at communication facilities that have terrain obstructions that cause a loss of communication at lower Air/Ground altitudes.
 RCAG generally consists of four radio antennas that allow ARTCC (RCAG) controllers to communicate with aircraft that are beyond the center’s normal antenna range.

Mod 3
 Integrity - the ability of the system to monitor itself and provide timely warnings to users, or shut itself down when it should not be used for navigation.
 Accuracy - the ability of the system to show the true position of an aircraft at any time.
 Availability/reliability - the ability for NAVAIDs to provide the navigational service whenever it is needed by the user of the system. It is the percentage of time in a given period that the signal is expected to be received and usable.

Mod 3
 A visual approach is an approach when either part or all of an instrument approach procedure is not completed
(or was never initiated) and the approach is executed with visual reference to the terrain
 Can be made anytime ATC approves it, when the destination airport meets visibility requirements of three statute miles or greater, and the cloud ceiling height is at least 1,000 feet above the ground level

Mod 3
 A contact approach is a procedure that results from an instrument approach when the visibility is greater than one mile.
 In such cases, a pilot is cleared by ATC to make an instrument approach to land, and the pilot then uses visual reference to complete the approach when conditions allow.

Mod 3
 An instrument approach is an approach using horizontal and/or vertical guidance and is a procedure established by the FAA that outlines the routes and altitudes to be flown by an aircraft for safe flight from takeoff to landing.
 Instrument approaches can be either precision or nonprecision. Precision instrument approaches provide both vertical and horizontal guidance, whereas nonprecision instrument approaches provide only horizontal guidance.

Mod 3
 Specialized instrument approach and departure procedures are developed under guidelines known as Terminal Procedures
(TERPS) . The criteria for establishing TERPS allows for increased use of a runway during inclement weather, but it also mandates a flight path that can result in a concentration of noise impact on those beneath it.
 For departures, a pilot flying under normal instrument procedures follows a defined flight path that allows the aircraft to intercept an enroute flight path. These procedures are defined and published as Standard Departure (SD) procedures.
 A similar procedure to simplify communication and understanding is used for approaches. It is known as a STandard instrument (STAR) ARrival (STAR) procedure.

Mod 3

 Provides both vertical and horizontal electronic information to the pilot for purposes of aligning an aircraft with the centerline of a runway at the proper approach angle.
 Consists of
 A localizer beam radiating along the straight line of the approach
 A glide slope transmitter, which fans out from the approach end to provide height information
 An outer marker; a middle marker; and possibly inner marker
 An FAA-determined safe Decision Height (DH)
 An approach light system
Mod 3

ILS Category
I
I (with centerline and
TDZ lights and RVR)
Decision Height
200 feet
200 feet
II
IIIA
IIIB
IIIC
*
*
100 feet
*
Visibility or RVR
½ mile (2400 feet)
1800 feet
1200 feet
700 feet
150 feet
+
* Decision height not specified, only visibility limits apply
+Aircraft must have autoland capabilities and a qualified pilot
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Mod 3

 Both CAT II and CAT III ILS approaches require an airport to have RVR equipment, while a CAT I ILS can use trained visual observers or weather reporting equipment such as AWOS or
ASOS.
Mod 3
 Two types of RVR equipment
 The older style uses light and two devices located 500 feet apart and at least 250 feet on either side of the runway outside the safety area. One device is a transmissometer that projects a light beam of known intensity toward the second device, which is the receiver.
 Newer generation infrared forward scatter RVR use a single fiberglass pole with the transmitter and receiver located at angles to each other. These types of devices can display and report RVR data down to 100 feet visibility, in contrast to 200foot increments for the older style.

Mod 3

Mod 3

 A Category I runway requires only a single RVR at its midpoint or aiming point.
 Category II and III runways will have two or three RVRs, depending upon the visibility minimums. If two are required, one is at the touchdown point and the other at the rollout point. A third RVR, if necessary, is located at the midpoint of the runway.
Mod 3
 Calculation of visibility can also be determined through a runway visibility value (RVV) or by practical observation. The
RVV is determined through instrumentation that attempts to replicate what a pilot would actually see during an approach.
The RVV values are reported in portions of a mile.

Mod 3
 Projects a radio frequency (RF) beam down the runway from the departure end toward the approach end. The signal fans out narrowly along its path toward the centerline of the runway. This component provides lateral guidance, assisting the pilot in aligning the aircraft with the runway centerline. A localizer-only approach is considered a non-precision approach.
 LDA is a localizer used for approach guidance to an airport, but is usually offset from the centerline of the runway. In this case, the signal does not align the aircraft with the centerline of the runway and cannot be part of a complete ILS.
 The localizer is an antenna array normally located more than 1,000 feet past the departure end of the runway having the approach.
The 1,000 foot requirement places it outside the runway end object free area.

Mod 3

Mod 3
 The impact critical area zone, known as the localizer critical area , can be 500 feet in diameter around the antennas, 400 feet wide, and extend 2,000 feet down the runway. Aircraft and vehicles must remain clear of the localizer critical area while it is in use for aircraft approaches.

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Mod 3
 The major component of an ILS system.
 The GS is normally located at least 250 feet on either side of the instrument runway and 1,000 feet past the approach landing threshold.
 Provides the pilot with vertical height information and transmits a signal that normally results in a three-degree approach slope away from the runway end.
 The glide path angle results in a Threshold Crossing Height
(TCH) that is published in the instrument charts for safety reasons.
 The GS critical area is normally rectangular in shape and covers an area 500 feet wide by 1,200 feet long directly in front of the antenna.

Mod 3

 Provides the pilot with range information to the threshold. This is accomplished by their fixed distance location along the localizer approach path. The marker beacon signals are cone- or fan-shaped, directed vertically into space, and annunciate an aircraft’s receiver as the aircraft passes overhead
 Category II and III ILSs have three marker beacons:
 Outer Marker (OM) - 4 to 7 nautical miles from the runway threshold
 Middle Marker (MM) - 2,000 to 6,000 feet from the runway threshold
 Inner Marker (IM) or a DME marker - 1,000 feet from the threshold
Mod 3

Mod 3

Mod 3
 An aircraft properly flying a CAT I approach will be at an altitude of 200 feet over the middle marker. It is at this point that the Decision Height (DH) for the approach is normally established.
 The DH is the point at which a pilot is required to have the runway threshold lights in view to continue the approach.
 If the threshold lights are not visible, the pilot must execute a missed approach.
 For non-precision approaches, there is Minimum Descent
Altitude (MDA) that a pilot maintains until the runway is visible.

Mod 3

Mod 3
 Signal is omnidirectional and can be received by an aircraft instrument (Automatic Director Finder, ADF) in the cockpit
 Only single, short vertical antenna and normal electrical power are required for operation
 Used primarily where bad terrain exists or if cost consideration dictates its use
 Signal acts as a homing device for aircraft
 Subject to environmental disturbances (electrical storms)
 NOTAM issuance in the event of outage
 Understand any alarm system operation
 Provide routine site inspection
 When used as an ILS MM, OM, or Final Approach Fix (FAF) is called Compass Locator
 Requires local altimeter setting, through ATC or AWOS/ASOS.
 Being phased out due to GPS, etc.

Mod 3

 Transmits VHF radio signals in a finite number of compass headings
 Not greatly affected by lightning static or terrain reflection
 Signals are line-of-site
 Tactical Air Navigation (TACAN) - military’s version of VOR system – Ultrahigh frequencies (UHF)
 VORTAC - VORs and TACANs co-located
 Critical and sensitivity areas- 750 to 1,000-foot radius
 Terminal VOR (TVOR)
 Located on airport
 R ange of 25-40 miles
 Use for instrument approaches & local navigation
 VOR ground checkpoints - pavement marking & sign VOR identifier, frequency
Mod 3

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 At those airports where siting or cost factors preclude installation of an ILS system, a simplified directional facility (SDF) may be installed to provide increased runway use during inclement weather. An SDF provides course information similar to a localizer, but it is less accurate, while also being more flexible given the surrounding environment.

 Distance Measuring Equipment (DME)
 Provides information on how far the aircraft is from the station
 Microwave Landing Systems (MLS)
 Planned civilian application
 Provided for a number of multiple curved and segmented approaches - overcome limitations of ILS
 Shortens the approach time
 Avoids noise-sensitive areas
 Provide guidance during missed approach
 But, these benefits were overshadowed by GPS
Mod 3

Mod 3
 Satellite-based navigation system
 Better accuracy
 Provides velocity information
 Signals less susceptible to interference or error
 Line of sight availability
 Minimum of four satellites is necessary to establish an accurate three-dimensional position.
 Selective Availability (SA) is a method by which the accuracy of GPS is intentionally degraded. This feature is designed to deny hostile use of precise GPS positioning data. SA was discontinued on May 1, 2000, but many GPS receivers are designed to assume that SA is still active.

Mod 3

Mod 3
 When GPS equipment is not using integrity information from WAAS or LAAS, the GPS navigation receiver using Receiver Autonomous Integrity
Monitoring (RAIM) provides GPS signal integrity monitoring.
 RAIM is necessary since delays of up to two hours can occur before an erroneous satellite transmission can be detected and corrected by the satellite control segment.

Mod 3
 WAAS
 Ground-based reference station
 GPS accuracy to within 30 feet
 24 ground-based stations & 24 orbiting satellites
 Satisfy Category I instrument approach needs
 WAAS enables area navigation (RNAV), lateral navigation guidance (LNAV), vertical navigation (VNAV), and localizer performance with vertical guidance (LPV) approaches at airports, providing similar benefits as a Category I ILS, but without the expense.

 GBAS
 Provide for GPS approaches to Category II or III minimums
 Ground-based transmitter on, or close to, an airport
 Lower power and range than WAAS
 The equipment consists of a GBAS Ground Facility (GGF), four reference stations, a VHF Data Broadcast (VDB) uplink antenna, and an aircraft GBAS receiver.
 Formerly Local Area Augmentation System (LAAS).
 Places a ground-based transmitter in close proximity to, if not on, an airport.
Mod 3
 It performs the same function as the WAAS, which is to augment the satellite transmitters and to verify the satellite signals. However, it is of a lower power and range, as its purpose is to satisfy the need for accuracy and the number of transmitters for an aircraft to make a Category II or III approach to a runway.

Mod 3
 Enhances ATC ability to identify and guide aircraft.
 Pilots also benefit from ADS-B with enhanced traffic and weather information in the cockpit.
 GPS is used as the ADS-B position source for aircraft today, allowing for an increase in the accuracy of information that is being provided to ATC and pilots.
 ADS-B enables properly equipped aircraft to broadcast their identification, position, altitude, and velocity to other aircraft and to ATC. This is known as ADS-B Out.
 The receipt by an aircraft or vehicle of ADS-B data is known as
ADS-B In (a cockpit display is required to receive this data).
 By 2020, all aircraft operating within designated ADS-B airspace will be required to comply with the equipment performance requirements of ADS-B Out.

Mod 3

Mod 3
 Radio Detection and Ranging (RADAR)
 Four components
 Transmitter
 Antenna
 Receiver
 Display
 Transponder-beacon device installed on the aircraft, which is used to transmit data about the aircraft’s position and altitude
 Sqawk – Discrete code an assigned aircraft transmits on the transponder
 Mode S – Provides interrogation and transfer of high-density data, such as speed, rate of climb, weather, clearances, and traffic info
 Critical and sensitivity areas - 1,000 feet radius

Mod 3

 Air Route Surveillance Radar (ARSR)
 Airport Surveillance Radar (ASR)
 Precision Approach Radar (PAR)
 Airport Surface Detection Equipment (ASDE) radar
 Primary surveillance radar
 Uses a continually rotating antenna mounted on a tower to transmit electromagnetic waves that reflect, or backscatter, from the surface of aircraft up to 60 miles from the radar. The radar system measures the time required for radar to echo to return and the direction of the signal.
 Secondary radar
Mod 3
 Uses a second radar antenna attached to the top of the primary radar antenna to transmit and receive area aircraft data for barometric altitude, identification code, and emergency condition.

Mod 3
 Two types of surveillance radar cover the airspace
 (1) search radar (technically termed primary ASR radar)
 (2) the Air Traffic Control Radar Beacon system (called ATCRB or ATCRB secondary radar)
 Drawbacks with primary radar systems
 (1) they are very susceptible to atmospheric conditions and the size of the target
 (2) they do not provide information about the aircraft’s altitude.
 To overcome these deficiencies, the ATCRB system was developed to require aircraft to have a transponder that receives the secondary radar signal and responds with a reply signal

 The ATCRB system evolved over time into the Automated Radar
Terminal System (ARTS), which has the capability to predict flight paths, determine conflicts with other aircraft, receive altitude information, and transmit/receive other important aircraft identification information.
 Two major types of Automated Radar Terminal System (ARTS) models in use at FAA facilities –
 ARTS IIE
 Designed to support one or two sensors and up to 22 displays in two different configurations that can process 256 simultaneous tracks per sensor.
 ARTS IIIE
 Designed to support 15 sensors, 10,000 simultaneous tracks, and over 200 displays.
 ARTS-IIIE is operational at 8 large TRACONs.
Mod 3

 Precision Runway Monitoring
 Installed in conjunction with ARTS III
 Allows for enhanced and more accurate radar information on aircraft so that controllers can monitor two aircraft simultaneously to make certain they do not stray into a notransgression zone between the two approaches.
Mod 3

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Mod 3
 Purpose is to augment and confirm information on aircraft/vehicle positions on ground
 ASDE-3 and ASDE-X
 Ground mapping radar system
 Locates & displays locations of aircraft & vehicles
 ASDE-s receives information from three sources (ASDE,
ARTS, and multilateration sensors), rather than the single radar source of ASDE-3

Mod 3

Mod 3
 Airport Movement Area Safety System (AMASS)
 Conflict alert mechanism, works in conjunction with
ASDE & ARTS
 Predicts and help prevent runway incursions

 Airport Surface Traffic Automation (ASTA)
 Purpose - increase safety by reducing runway incursions and surface collisions, especially during low visibility
 Five elements:
1.
Runway status light system
2.
Surveillance data link
3.
Aural and visual warnings
4.
Data tags
5.
Traffic planner
 Aeronautical Data Link System (ADLS)
 Intended to replace or supplement many of today’s routine voice and analog data communications with more timely and accurate digital messages.
 Traffic Management System (TMS)
 Term used to describe an interactive, dynamic, flexible, and efficient system to managing air traffic
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Mod 3
 Commercially-based decision support system (DSS).
 OASIS incorporates functions currently provided by the graphic weather display, flight service data processing equipment, aviation weather processor, and direct user access terminal service.
 Self-service kiosks at airports give pilots instant flight service information.

Mod 3
 Airport is responsible for preventing the construction of facilities on its airport that would derogate the operation of an electronic or visual NAVAID and air traffic control facilities on the airport.
 The airport is also responsible for helping to prevent the interruption of visual and electronic NAVAID signals and for protecting all on-airport NAVAIDs against vandalism and theft.
 In the event of an aircraft accident involving the use of any navigational aid, the system is immediately shut down until it is rechecked and certified by the FAA.

Mod 1