Tech Prep - Instumentation

Question 1

IAS

Answer 1

Indicated Airspeed
Dynamic pressure as displayed on the AIS

Question 2

CAS

Answer 2

Calibrated Airspeed
IAS corrected for position and instrument errors
Larger modern ACFT ADCs display this, V speeds are in CAS

Question 3

EAS

Answer 3

Equivalent Airspeed
CAS corrected for compressibility
Vmo is in EAS

Question 4

TAS

Answer 4

CAS (EAS) corrected for temperature and pressure

Question 5

Mach number formula

Answer 5

38.94*(T(Kelvin)^½

Question 6

ASI errors (6 in total)

Answer 6

Instrument
Pressure
Density
Compressibility
Maneuver
Blocked pitot static system

Question 7

ASI error: static probe blockage

Answer 7

At constant altitude ASI reads correctly
During descend the ASI will over read
During climb, ASI will under read

Question 8

ASI error: dynamic probe blockage

Answer 8

At constant altitude the ASI is frozen
During descend the ASI will under read
During climb the ASI will over read

Question 9

Altimeter errors (7)

Answer 9

Instrument
pressure
time-lag
barometric
density
temperature
blockage

Question 10

Altimeter error: static port blockage

Answer 10

indicator stuck

Question 11

VSI errors (4)

Answer 11

instrument
time-lag
pressure
maneuver

Question 12

VSI error: statick probe blockage

Answer 12

indicator moves to 0 and does not change

Question 13

Slip vs Skid

Answer 13

Slip is lateral force into the turn
Skid is lateral force out of a turn

Question 14

Turn and slip indicator

Answer 14

2 degrees of freedom gyro
rotates about the horizon axis
one gimbal about the ACFTs lateral axis

Question 15

Magnetic compass:
ANDS
UNOS

Answer 15

Accelerate North Decelerate South
Undershoot North, Overshoot South

Question 16

Autopilot landing systems:
Fail-passive

Answer 16

In the event of a failure, controls handed back to the pilot without significant out of trim condition
typically:
Auto-monitored auto-pilot
Two autopilots auto-comparing eachother

Question 17

Autopilot landing systems:
Fail-operational

Answer 17

In the event of a failure, approach, flare and landing can still be completed by the remaining part of the system. Typically achieved via reverting back to fail-passive
Typical arrangements:
Two monitored APs, one remaining operative after failure
Three APs, two remaining operative after failure

Question 18

Fail-operational hybrid system

Answer 18

Typically one fail-passive system and a secondary independent guidance system enabling manual completion after a failure of the primary

Question 19

Frequency ranges:
NAV
COM
ILS
VOR
NAV aids enroute/terminal

Answer 19

NAV: 118.00-117.975
COM: 118.00-136.975
ILS: 108.000-111.975 ending 0/5 odd second digit
VOR 108.000-111.975 ending 0/5 even second digit
NAV aids enroute: 112.000-117.975