Question 291-1 : Which is the maximum distance at which you might expect solid vhf contact over flat terrain at flight level 100 ? [ Diploma registration ]

Question 291-2 : Which is the maximum distance at which you might expect solid vhf contact over flat terrain at flight level 50 ?

About 85 nm.

The theoretical reception range for a vhf transmission can be estimated with this formula fl 50 = 5000 ftsqrt square root123 x sqrt 5000 = 87 nm

Question 291-3 : Which of the following frequencies is an international emergency frequency ?

121500 mhz.

Icao annex 10 107icao annex 10 522113 recommendation aircraft on flights should guard the emergency frequency 1215 mhz to the extent possible

Question 291-4 : Which of the messages listed below shall not be handled by the aeronautical mobile service ?

Radio teletype messages.

Icao annex 10 107

Question 291-5 : Which phenomena will normally influence the reception of vhf transmission ?

Level of aircraft and terrain elevations.

Very high frequencies are line of sight frequencies with practically no ground wave element the vhf range increases with height

Question 291-6 : Frequency bands used in the aeronautical mobile service for radiotelephony are ?

Hf and vhf.

The aeronautical mobile service uses vhf for short range communications and hf for long range communications with amplitude modulation

Question 291-7 : A vhf signal is received with a certain power at 100 nm from an emitting station it will be received at 50 nm with a power ?

4 times stronger.

To increase the range of a radio transmission the power is increased by a square factor to double its range the power is increased by a 4 factor x2² therefore at 50 nm a signal will be 4 times stronger than the signal received at 100 nm

Question 291-8 : The frequency 121500 mhz is designated as ?

An international emergency frequency.

Question 291-9 : What is the maximum distance at which you may expect strong vhf reception over flat terrain at fl 140 ?

About 140 nm.

Question 291-10 : All aircrafts entering the european region above fl195 are required to have a receivertransmitter with channel separation ?

833 khz.

Question 291-11 : What is vhf frequency range ?

30 300 mhz.

Question 291-12 : Your aircraft is in flight over the ocean at 18000 ft you receive a distress call from another aircraft in his last message he indicated to be at 2000 ft and signal weakening assuming no attenuating factors in the effective range of vhf transmissions how far the distress traffic is located from your ?

220 nm.

Question 291-13 : Due to an engine failure you have to perform an emergency ditching you are in contact with a ground station located at 400 ft amsl at a distance of 150 nmat which distance you will lose the contact ?

10500 ft.

For coverage and range to calculate the range in nm official learning objectives formula is 123 x square root transmitter height in feet + 123 x square root receiver height in feet123 x sqrt400 + 123 sqrt = 150 nm sqrt square root 246 nm + 123 x sqrt = 150 nm123 x sqrt = 150 nm 246123 x sqrt = 1254 nm1254 123 = 1019510195² = 10394 ft

Question 291-14 : Due to an engine failure you have to perform an emergency ditching you are in contact with a ground station located at 400 ft amsl and you are at 10500 ft amslthe ground station is at a distance of ?

150 nm.

For coverage and range to calculate the range in nm official learning objectives formula is 123 x square root transmitter height in feet + 123 x square root receiver height in feet123 x square root 400 + 123 x square root 10500 = 150 nm

Question 291-15 : What are the most unfavorable conditions for vhf wave propagation ?

High air density with a high frequency.

Question 291-16 : At fl 350 above a flat terrain you may expect good vhf reception at a maximum distance of a ground station of about ?

234 nm.

You have to use the following formula maximum range = 123 x square root height in feet fl 350 = 35000 ftmaximum range = 123 x sqrt 35000 = 123 x 187 = 230 nmwe may expect a good vhf reception not a strong vhf reception

Question 291-17 : The maximum distance at which you might expect solid vhf contact over flat terrain at flight level 100 is about ?

120 nm.

The theoretical reception range for a vhf transmission can be estimated with this formula 123 x sqrt 10000 = 123 nm sqrt square root fl 100 ==> 10000 ft

Question 291-18 : Under which of the following circumstances may you expect a solid reception of the tower frequency 1182 mhz ?

Aircraft at high level in the vicinity of the ground station.

Question 291-19 : Which is the frequency band containing frequencies of the aeronautical mobile service ?

118000 136975 mhz.

Question 291-20 : The frequency bands 118000 to 136975 mhz allocated to the aeronautical mobile service are in the band of ?

Very high frequency.

Question 291-21 : Which of the following broadcast in the vhf frequency band is least likely to be affected by attenuation ?

Two aircraft in contact at 30000 ft.

Question 291-22 : The conditions to obtain the maximum transmission distance which ensure the best transmission will be obtained with the following parameters ?

Question 291-23 : An aircraft's vhf radio is replaced with a new unit with 3 times more powerwhat will be the increase in transmission range ?

17 times.

Question 291-24 : What does selcal mean ?

A system which permits the selective calling of individual aircraft over radiotelephone channels linking a ground station with the aircraft.

Question 291-25 : What does tcas mean ?

Traffic collision avoidance system.

Question 291-26 : What does acars mean ?

Aircraft communication addressing and reporting system.

Question 291-27 : When a tcas resolution advisory ra requires deviation from an atc clearance pilots should report ra to the controller as soon as practicable after he starts to deviate with his aircraft call sign plus the phraseology ?

Tcas ra.

Question 291-28 : After the resolution advisory ra response is completed and a return to the atc clearance or instruction is initiated pilot should use the following phraseology ?

Clear of conflict returning to assigned clearance .

Question 291-29 : After the response to a resolution advisory ra is completed and the assigned atc clearance or instruction has been resumed pilot should use the following phraseology ?

Clear of conflict assigned clearance resumed.

Question 291-30 : In the event that the controller issued a clearance or instruction contradictory to the tcas resolution advisory the flight crew will follow the ra and inform the controller ?

Unable tcas ra.

Question 291-31 : The controller shall not attempt to modify the aircraft flight path until the pilot announces ?