A01
From the ARP4754A:
AIRWORTHINESS: The condition of an aircraft, aircraft system, or component in which it operates in a safe manner to
accomplish its intended function.
FAILURE CONDITION CLASSIFICATIONS: A discrete scale allowing categorization of the severity of the effects of a
failure condition. The classification levels are defined in the appropriate CFR/CS advisory material (section 1309):
Catastrophic, Hazardous/Severe-Major, Major, Minor, or No Safety Effect.
EXTERNAL EVENT: An occurrence which has its origin distinct from the aircraft or the system being examined, such as
atmospheric conditions (e.g., wind gusts/shear, temperature variations, icing, lightning strikes), operating environment
(e.g. runway conditions, conditions of communication, navigation, and surveillance services),, cabin and baggage fires,
and bird-strike. The term is not intended to cover sabotage.
A02
Environmental Parameters:
Total Pressure:
Static Pressure:
Dynamic Pressure:
Total Temperature (TAT):
Static Temperature (SAT):
Reduced vertical separation minima (RVSM): A controlled airspace where aircraft are allowed to fly with a reduced vertical separation from 600m to 300m. Meaning that more aircraft can exist in the volume of airspace, but require much more accurate control to avoid collision.
Speeds:
TAS: True Air Speed; Equivalent airspeed corrected for density (temperature/pressure) affects due to altitude
IAS: Indicated Airspeed; raw indicated airspeed from the pitot-static tube system
CAS: Calibrated Airspeed; Indicated airspeed corrected for instrument and positioning error
EAS: Equivalent Airspeed; Calibrated airspeed corrected for compressibility effects at airspeeds approaching speed of sound
GS: Ground Speed; actual speed of the aircraft relative to the ground
Sensors
Pitot Tube: Measures the total pressure of the oncoming fluid, taking away the static pressure leaves the dynamic pressure which is used to find airspeed
Static Port: Measures the static pressure of the fluid, removing this from total pressure leaves dynamic pressure (usually this is done with a diaphragm)
TAT Probe: Measures the local total air temperature
AOA Probe: Measures the angle of attack of the oncoming fluid.
Instruments:
IAS Indicator: Indicates raw airspeed value from pitot-static tube system; some have functionality to calculate true airspeed based on environmental temperature input.
Machmeter: Displays the mach number of the aircraft (speed relative to the local speed of sound) using the pitot-static tube system. Only present on aircraft where this would be operationally relevant.
Altimeter: Uses pressure from the static port to approximate the aircraft altitude.
Vertical Speed Indicator: Uses the static port to determine aircraft vertical speed (usually in 100ft/min)
TAT Indicator: Displays the local total air temperature from the TAT probe through electrical connections.
AOA Indicator: Displays the angle of attack of the aircraft using electrical data from the AOA probe.
Digital Systems:
ADC: Air Data Computer
ADS: Air Data System
ACARS: Aircraft Communications Addressing and Reporting System. a digital datalink system for transmission of short messages between aircraft and ground stations via airband radio or satellite.
ADS-B: Automatic Dependent Surveillance–Broadcast. Allows an aircraft to determine its position via satellite navigation or other sensors and periodically broadcasts its position and other related data, enabling it to be tracked. Forms part of the aircraft collision avoidance system.
IRS: Inertial Reference System
ADIRS: Air Data and Inertial Reference System. Combination of both the ADC and IRS which allows for additional parameters to be calculated such as wind direction and speed, groundspeed (GS) and Wind Correction Angle (WCA).