Electronic Navigation System

Question 1

Rule of 5

Answer 1

No. 1 bearing pointer - doppler/gps
No. 2 bearing pointer - adf/vor
course deviation bar - doppler/gps / vor/ localizer
course deviation pointer - doppler/gps / vor/ localizer / fm home
roll command bar - doppler/gps / vor/ localizer / fm home / heading

Question 2

Heading mode

Answer 2

Processes heading error and roll attitude signals to provide a cyclic command which when followed will allow the helicopter to track the selected heading

one overshoot

1 degree of roll command for each degree of heading error up to 20 degrees

tracking error no more than 2 degrees

Question 3

Altitude hold

Answer 3

processes barometric pressure signals

provides collective command signals to maintain altitude +/- 50 feet

limits must be vertical rate of 200 fpm or less, altitude between -1000 to 10000 feet and airspeeds 70 - 150 its

Question 4

VOR NAV mode

Answer 4

initial course intersection will be made in heading mode when within 10 - 20 degrees

When wishing 10 - 20 of selected course CISP turns off HDG provides final course intercept about 45 degrees

one overshoot range of 10 NM speed 100 =/- 10 kts
two overshoots between 5 and 40 NM speed 70 - 140 kts

Question 5

ILS NAV mode

Answer 5

Input localizer frequency and select NAV

airspeed +/-5 of IAS when engaged

barometric altitude / collective stick signals provide collective position indication - ALT turns ON

need desired course on deviation bar

one overshoot range 10 NM at 100+10 kts
2 overshoots 5 - 20 NM speeds 70 - 130 kts

Question 6

Approach mode - ILS

Answer 6

ILS NAV - will auto engage when glide slope captured

• alt mode disengages

collective position indicator transitions from alt hold to glide slope path acquisition tracking
cclic roll commands limited to 15 degrees

Question 7

BACK CRS mode

Answer 7

submode of ILS - engaged by concurrent ILS on and back crs on signal from HSI/VSI mode selector - will allow pilots to back course localizer approach

Question 8

Level - off Mode

Answer 8

VOR NAV or ILS NAV modes - deactivated by selection of another mode or when radar altitude valid signal is not present

barometric altimeter must be used to determine arrival at the minimum altitude

engaged when radar goes below low altitude warning bug setting

CISP provides collective pointer command maintain altitude within 10 feet of bug for below 250 feet or 20 feet if above 250 feet

Question 9

Go Around

Answer 9

cyclic roll, cyclic pitch, collective position indication,

• CISP provides collective position indications resulting in 500 +/- 50 fpm rate of climb at zero bank angle
• 5 seconds after engaged will get a 80 KTs pitch bar command
• disengaged by changing to any mode on CIS

Question 10

Doppler / Doppler/GPS

Answer 10

course sensitivity +/- 1000 meters when farther than 12 km to destination. changes to +/- 200 meters at 2 km from destination.

Question 11

Alt hold paramenters

Answer 11

Air speed - 70 - 150 kts
climb > 200 fpm
altitude -1000 thru 10,000ft

Question 12

hdg hold

Answer 12

no wind correction

1 to 20 degree error

roll command bar

keep within 2 degree of heading selected