Instrument Systems
Pitot-static and air data, gyroscopic/AHRS instruments, EFIS/EICAS and the FDR/CVR recorders.
Instrument systems, summary notes
- The PITOT-STATIC system feeds the pressure instruments: the STATIC port feeds the altimeter, ASI and VSI, while the PITOT probe feeds only the ASI; air data computers (ADCs) now compute airspeed, altitude and Mach electronically.
- ATTITUDE and HEADING come from gyroscopic instruments or modern AHRS/IRS (laser/ring gyros), displayed on the EFIS, the primary flight display (PFD) and navigation display (ND).
- EICAS/ECAM centralise engine and system indication with alerting; standby instruments and a standby power source provide a backup if the main displays fail.
- Mandatory RECORDERS, the flight data recorder (FDR) and cockpit voice recorder (CVR), the 'black boxes', capture parameters and audio for accident investigation and are crash/fire-protected.
- A central warning/caution system prioritises alerts; data is shared over ARINC 429/629 digital buses.
- ⚠ Exam trap: the STATIC source feeds the altimeter, ASI and VSI (pitot feeds only the ASI); the FDR and CVR are the crash-protected 'black boxes', the FDR records flight parameters, the CVR records cockpit audio.
What are the two mandatory crash-protected recorders and what does each capture?
The Flight Data Recorder (FDR) continuously records a large set of aircraft parameters (attitude, speed, altitude, control positions, engine data, etc.), and the Cockpit Voice Recorder (CVR) records the flight-deck audio (crew speech, radio and ambient sounds). Both are housed in crash- and fire-resistant units with underwater locator beacons, so investigators can recover the data after an accident.
Pitot-static system & blockage failures
Gyroscopic rigidity & precession
Instrument systems concept map
Instrument Systems
Instrument systems quiz
Instrument Systems, quiz
1. The static port feeds:
Altimeter, ASI and VSIASI onlyThe compass2. The pitot probe feeds:
The airspeed indicatorThe altimeterThe VSI3. The 'black boxes' are the:
FDR and CVRADC and AHRSCSD and IDG4. The FDR records:
Flight parametersCockpit audio onlyFuel price5. The CVR records:
Cockpit audioFlight parametersCabin temperature6. An air data computer computes:
Airspeed, altitude and Mach from pressuresFuel quantityCabin altitude only7. EFIS displays are the:
PFD and NDFDR and CVRCSD and TRU8. A blocked static source makes the altimeter:
Freeze at the last readingRead zeroOver-read rapidly