Tech Prep - Instumentation Flashcards
IAS
Indicated Airspeed
Dynamic pressure as displayed on the AIS
CAS
Calibrated Airspeed
IAS corrected for position and instrument errors
Larger modern ACFT ADCs display this, V speeds are in CAS
EAS
Equivalent Airspeed
CAS corrected for compressibility
Vmo is in EAS
TAS
CAS (EAS) corrected for temperature and pressure
Mach number formula
38.94*(T(Kelvin)^½
ASI errors (6 in total)
Instrument
Pressure
Density
Compressibility
Maneuver
Blocked pitot static system
ASI error: static probe blockage
At constant altitude ASI reads correctly
During descend the ASI will over read
During climb, ASI will under read
ASI error: dynamic probe blockage
At constant altitude the ASI is frozen
During descend the ASI will under read
During climb the ASI will over read
Altimeter errors (7)
Instrument
pressure
time-lag
barometric
density
temperature
blockage
Altimeter error: static port blockage
indicator stuck
VSI errors (4)
instrument
time-lag
pressure
maneuver
VSI error: statick probe blockage
indicator moves to 0 and does not change
Slip vs Skid
Slip is lateral force into the turn
Skid is lateral force out of a turn
Turn and slip indicator
2 degrees of freedom gyro
rotates about the horizon axis
one gimbal about the ACFTs lateral axis
Magnetic compass:
ANDS
UNOS
Accelerate North Decelerate South
Undershoot North, Overshoot South
Autopilot landing systems:
Fail-passive
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
Autopilot landing systems:
Fail-operational
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
Fail-operational hybrid system
Typically one fail-passive system and a secondary independent guidance system enabling manual completion after a failure of the primary
Frequency ranges:
NAV
COM
ILS
VOR
NAV aids enroute/terminal
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
