The Six Pack: Aircraft Instruments Explained

Overview

The Six Pack refers to the six basic aircraft instruments that provide pilots with crucial flight data, including speed, altitude, climb/descent rate, attitude, heading, and turning/banking information. These instruments are:

• Airspeed Indicator (ASI)
• Altimeter
• Vertical Speed Indicator (VSI)
• Attitude Indicator (AI)
• Heading Indicator (HI)
• Turn Coordinator (TC)

Instrument Systems

Pitot-Static System

• Instruments: ASI, Altimeter, VSI
• Components:
  • Pitot tube (for ASI)
  • Static port (for ASI, Altimeter, VSI)
• Function: Provides pressure data for speed and altitude calculations.

Gyroscopic Instruments

• Instruments: AI, HI, Turn Indicator
• Power Sources: Vacuum, pressure, or electrical power.

Instrument Details

Airspeed Indicator (ASI)

• Function: Measures aircraft speed using pressure differential from pitot-static system.
• Unit: Knots or miles per hour.
• Markings:
  • White Arc: Flap operating range (VS0 to VFE)
  • Green Arc: Normal operating range (VS1 to VN0)
  • Blue Line: Best single-engine climb speed
  • Yellow Arc: Caution area (VN0 to VNE)
  • Red Line: Never exceed speed (VNE)

Attitude Indicator (AI)

• Also Known As: Artificial Horizon
• Display: Miniature aircraft against a horizon line, indicating pitch and bank angles.
• Components: Internal gyro provides attitude data.

Altimeter

• Function: Displays altitude above mean sea level (MSL).
• Mechanism: Uses static port for barometric pressure data.
• Adjustment: Baro setting for local pressure adjustment.

Turn Coordinator (TC)

• Function: Displays roll rate and stabilized turn rate.
• Components: Internal gyro, liquid-filled inclinometer for slip/skid indication.
• Note: Does not indicate bank angle.

Heading Indicator (HI)

• Function: Displays aircraft heading using a compass rose.
• Components: Gyro-driven, adjustable to align with magnetic compass.
• Display: 360-degree compass card, 5-degree increments.

Vertical Speed Indicator (VSI)

• Function: Indicates climb or descent rate in hundreds of feet per minute.
• Mechanism: Diaphragm connected to static port, responds to pressure changes.

About Mid-Continent Instruments and Avionics

• Specialists in manufacturing aircraft instruments and avionics, serving global aerospace markets.
• Provides sales, maintenance, and overhaul services in over 70 countries.

Additional Resources

• Find an Avionics Dealer: Link provided for locating dealers.
• Download Product Catalog: Available for 2025 offerings.