Avionics & Flight Operations
3 items
ARINC 429 digital avionics bus protocol, international transponder squawk codes, and barometric altimeter pressure subscale settings.
Items (3)
CompareAltimeter Pressure Settings
4 specs
Barometric altimeters compute aircraft height based on atmospheric pressure subscale settings: QNH (altimeter indicates true altitude above Mean Sea Level), QFE (altimeter indicates height above airport runway threshold), and QNE (standard 29.92 inHg / 1013.25 hPa for Flight Levels above transition altitude).
ARINC 429 Data Bus
6 specs
The ARINC 429 standard is the predominant two-wire differential data bus used across commercial and transport avionics, transmitting 32-bit digital words over a single transmitter / multi-receiver shielded twisted pair using Bipolar Return-to-Zero (BPRZ) modulation.
Transponder Squawk Codes
7 specs
Air traffic control secondary surveillance radar (SSR) interrogates airborne transponders to receive 4-digit octal Squawk Codes (digits 0–7), with internationally reserved codes for emergency conditions: 7500 (Hijacking), 7600 (Radio Failure), and 7700 (General Emergency).