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Main / Avionics

Each aircraft has a Pilot Operating Handbook on board which contains operations procedures, limits, performance, systems functionality and weight/balance information.


  • The tachometer shows RPMs.
  • Slats are the leading edge of wing; on some aircraft they can be extended at low speeds to reduce stall speed
  • An anti-servo tab is used to provide weight for light control surfaces for stability
  • Brakes are connected independently to the rudder pedals
  • the magneto keeps engine running despite battery and alternator failure, there are 2 for redundancy, and they provide current for the sparkplugs; known for reliability but also inefficient; powered by turning crankshaft; it functions as an alternator but using a permanent magnet
  • the alternator is engine driven and supplies electricity at 14-28V, turning mechanical energy into AC
  • the battery is relied upon for engine starting, and clock/meter power, and is a backup for a failed alternator
  • Engine can still start if battery and master switches off if magnetos are switched on and the prop is turned

The pitot-static systems are pressure sensitive instruments for airspeed, altitude, and vertical speed (VSI).

The definition of a stall is being at/above critical angle of attack, rather than being below a particular airspeed. Traditionally AOA indicators have not been included in cockpits.

OBS is the omni-bearing selector, part of the course deviation indicator.

The six-pack of primary instruments consists of

  • Airspeed indicator
  • Attitude indicator (horizon)
  • Heading
  • Vertical speed indicator (VSI)
  • Altimeter
  • Turn coordinator


  • ADC = air data computer (attitude, air speed, vert speed, air temp, AoA, pressures)
  • AHRS = attitude/heading reference system (attitude, heading, rates, acceleration)
  • OAT = outside air temp

Cockpit Displays

The Primary Flight Display (PFD) is a modern generation glass display that can replace the old six-pack. It shows the artificial horizon, with airspeed ruler view, altitude digits, turn coordinator overlay, and heading.

The Flight Management System (FMS) would be a separate screen that shows a moving map, for example.

FAA and Aviation Acronyms

  • AD = airworthiness directive
  • ADS-B = automatic dependent surveillance-broadcast; constantly transmitting location beacon
  • AIM = aeronautical information manual
  • AIS = aeronautical information services
  • ANSP = air navigation service provider
  • AOC = airline operational control
  • ATS = air traffic services
  • CAM = civil aeronautics manuals
  • CAR = civil air regulations
  • CFR = code of federal regulations
  • C2 = command & control
  • COE = common operating environment
  • DAA = detect and avoid
  • DAR = designated airworthiness rep
  • DER = designated engineering rep
  • FAR = federal aviation regulations
  • FBO = field base office
  • FIS = flight information services
  • ICAO = international civil aviation organization
  • MASPS = minimum aviation system perf standards
  • MOPS = minimum operation perf standards
  • MIS = meteorological information services
  • PMA = parts manufacturer approval
  • RNP = required nav perf
  • SAD = small airplane directorate (based in KC)
  • STC = supplemental type certificate
  • SUA = special use airspace
  • TOAC = time of arrival control

Process Acronyms

  • AC = air circular (AC 20-156 defines network cert plan)
  • ARP = aerospace recommended practice
  • ICA = instructions for continued airworthiness
  • CSAT = cyber security advisory team
  • DAH = design approval holder
  • IMS = integrated master schedule
  • PH = procedure handbook
  • PRA = particular risk assessment
  • PSCP = product specific cert plan
  • SOI = stage of involvement
  • SRT = system review team
  • TC = type certificate
  • TSO = technical standard order (minimum perf)

Flight Software

NASA's philosophy is test what you fly, fly what you test. In other words, don't do your testing, and then change the code!


Legacy backplane for GA is typically ARINC 429, RS-422/232 serial, and analog. In developing a replacement backplane, we want to upgrade this to Ethernet. The Ethernet standard used on 787 and A380 is ARINC 664 aka AFDX. We require redundancy and minimal latency (spec 150us stack climb per node). We might set a target of 2 hops max, with 500 byte size. How about reliable UDP as an analogy? One example of Kingnet = session layer headers. Here is the stack:


Here's our frame prototype with bit field width:

| version,2 | control/spare,6 | seqnum,8 | acknum,8 | mcast-dest,8 | msg-type,16 | data,? | CRC |

Message type defines data and widths.

Design Assurance Level

A means 9+ people could be killed if something went horribly wrong (not GA). E has no effect on critical systems.

For B/C, plan writers and reviewers must be independent. Every level requires 100% SCC (structural code coverage). Code -> review analysis -> unit integration -> system test. Level B includes branch checking, every scenario and C includes 100% SCC. VectorCast helps achieve this.

TC = type certificate for airframes, engines, props, etc.

Page last modified on January 15, 2024, at 12:58 PM