Flight Instruments

Flight instruments provide critical information about the aircraft’s performance and position. A clear understanding of these instruments is essential for safe and efficient flying. Most training aircraft, such as the Cessna 172, feature a standard "six-pack" of flight instruments, which are the foundation of instrument flying.

The Six-Pack of Flight Instruments

The "six-pack" refers to the six primary flight instruments arranged in a standard layout in many training aircraft. These instruments are divided into two categories: pitot-static instruments and gyroscopic instruments.

1. Airspeed Indicator (Pitot-Static)

The airspeed indicator shows the aircraft’s speed through the air in knots. It uses both the pitot tube and static port to measure dynamic pressure.

• Color Bands: Different colors indicate important speed ranges:
  • White Arc: Flap operating range.
  • Green Arc: Normal operating range.
  • Yellow Arc: Caution range (only in smooth air).
  • Red Line: Never exceed speed (V_ne).

Tip: Always monitor airspeed during climbs, descents, and turns to avoid stalling or exceeding speed limits.

2. Altimeter (Pitot-Static)

The altimeter measures the aircraft’s altitude above mean sea level (MSL) by comparing atmospheric pressure from the static port to a standard pressure setting.

• Kollsman Window: Adjust the altimeter to the current barometric pressure provided by ATC or AWOS/ASOS.
• Practical Use: Monitor altitude closely during climbs, descents, and level flight to maintain situational awareness and comply with ATC instructions.

3. Vertical Speed Indicator (VSI) (Pitot-Static)

The VSI shows the aircraft’s rate of climb or descent in feet per minute (fpm). It uses static pressure changes to indicate trends in vertical movement.

• Trend Information: Shows whether the aircraft is climbing or descending.
• Rate Information: Displays the rate of climb or descent.

Tip: Use the VSI to maintain a steady climb or descent and avoid rapid altitude changes.

4. Attitude Indicator (Gyroscopic)

The attitude indicator displays the aircraft’s orientation relative to the horizon. It shows pitch (nose-up or nose-down) and bank (left or right) angles.

• Artificial Horizon: A miniature airplane symbol aligns with the horizon bar to indicate the aircraft’s attitude.
• Practical Use: Essential for instrument flying and maintaining level flight in low visibility conditions.

Tip: Use the attitude indicator as your primary reference for maintaining a stable flight attitude.

5. Heading Indicator (Gyroscopic)

The heading indicator shows the aircraft’s direction relative to magnetic north. Unlike a magnetic compass, the heading indicator is stable and unaffected by turns or acceleration.

• Periodic Adjustment: Must be aligned with the magnetic compass periodically during flight to account for gyroscopic drift.
• Practical Use: Use the heading indicator for navigation and maintaining assigned headings from ATC.

Tip: Cross-check the heading indicator with the magnetic compass every 15 minutes to ensure accuracy.

6. Turn Coordinator (Gyroscopic)

The turn coordinator provides information about the rate of turn and coordination (slip or skid) during turns.

• Rate of Turn: The miniature airplane symbol shows whether the turn rate is standard (2 minutes for a full 360° turn).
• Slip/Skid Ball: Indicates coordinated flight. Keep the ball centered using rudder input.

Tip: Use the turn coordinator to maintain coordinated flight and avoid unintentional slips or skids.

Additional Instruments

In addition to the six-pack, modern training aircraft may include digital displays and additional instruments:

• Magnetic Compass: A backup for the heading indicator, providing direction relative to magnetic north.
• Engine Instruments: Monitor engine performance, including RPM, oil pressure, and oil temperature.
• Glass Cockpit Displays: Modern aircraft may feature Primary Flight Displays (PFD) and Multi-Function Displays (MFD) instead of analog instruments.

Practical Tips for Student Pilots

• Learn the Basics: Familiarize yourself with the six-pack layout and the function of each instrument.
• Scan Effectively: Practice scanning the instruments in a systematic way to maintain situational awareness. Avoid fixating on one instrument.
• Cross-Check Instruments: Compare readings from multiple instruments to confirm accuracy (e.g., airspeed, attitude, and VSI during a climb).
• Ask Questions: If you’re unsure about how an instrument works, ask your instructor for clarification or review the Pilot Operating Handbook (POH).

Conclusion

Flight instruments are essential tools for understanding your aircraft’s performance and position. By learning how each instrument works and practicing effective scanning techniques, you’ll develop strong situational awareness and confidence during flight. Work closely with your instructor to master both analog and digital instruments as part of your training.