Communication & Navigation Systems Flashcards
22 Questions
Is a certificated airframe mechanic allowed to adjust a communications transmitter?
No, this requires a license issued by the Federal Communications Commission.
Which frequency band is used for most aircraft communications?
The VHF band, between 30 and 300 megahertz.
What is the preferred location for a VOR antenna on an airplane?
On top of the aircraft, along the centerline of the fuselage.
In which frequency band does the VOR equipment operate?
In the VHF band, between 108.0 and 117.95 mega-hertz.
Which component of the Instrument Landing System shares the antenna with the VOR?
The ILS localizer.
In what frequency band does the DME equipment operate?
In the UHF band, between 962 and 1,024 megahertz and between 1,151 and 1,213 megahertz.
What is the preferred location for a DME antenna?
Along the centerline of the belly of the aircraft as far from any other antenna as is practical.
On what frequency is the marker beacon signal trans-mitted?
75 megahertz.
What do the three marker beacon lights indicate to the pilot?
The blue light indicates passage over the outer marker in an ILS approach, the amber light indicates passage over the middle marker, and the white light indicates passage over any other location specified on the instrument approach.
What precautions should be observed when working around aircraft radar?
The pulses of electrical energy transmitted from a radar antenna are strong enough that they can seriously injure a person struck by them. They can be reflected from nearby buildings and return with enough power to destroy the receiver circuitry. For this reason, aircraft radar should never be operated when there are people or buildings within 100 yards of the antenna sweep, and it must not be operated when the aircraft is being fueled or defueled.
Which frequency band is used for long range communications from an aircraft?
The high frequency band (2 to 25 megahertz).
What is meant by a transceiver?
A piece of radio communications equipment in which all of the circuits for the receiver and the transmitter are contained in one housing.
On what two frequencies does the Emergency Locator Transmitter operate?
121.5 and 243.0 megahertz.
Where is the ELT transmitter normally located on an aircraft?
In the tail of the aircraft or as far aft as possible, so it will be least likely to be damaged in a crash.
What three components of an Instrument Landing Are systems installed in an aircraft?
The receivers for the localizer, the glide slope, and the marker beacons.
What kind of antenna is used for VHF communications?
A vertically polarized whip antenna.
What kind of antenna is used for the ATC trans-ponder?
A UHF stubby antenna.
What is the preferred location for the ATC transponder antenna?
On the centerline of the belly of the aircraft as far from any other antenna as is practical.
What kind of conductor is used to connect a VHF or UHF antenna to its receiver or transmitter?
Coaxial cable.
What two types of antenna are used with most ADF receivers?
A directional loop antenna and a non directional sense antenna.
Why is it important that all shock-mounted electronic equipment be connected to the aircraft structure with a bonding braid?
The bonding braid is used to carry the return current from the equipment into the aircraft structure.
Why is it necessary to install a doubler on the inside of the aircraft skin when the antenna is mounted on the skin?
The doubler reinforces the skin so wind loads on the antenna will not cause the skin to flex and crack.
