UNRELIABLE INDICATIONS
Unreliable indications are one of the most challenging situations a pilot can face. You look at your instruments… but something feels off. Airspeed doesn’t match pitch. Altitude isn’t changing, even though you’re clearly climbing. At that moment, you have to stop trusting your screens—and start flying the aircraft by feel and procedure.
This scenario is rare, but when it happens, it can be deadly if mishandled. That’s why pilots train for it.
What are unreliable indications?
It usually refers to situations where primary flight instruments, like airspeed, altitude, or attitude, give wrong or conflicting information. This often involves pitot-static system failures, blocked sensors, or electrical faults.
Examples include:
- sudden loss or fluctuation of airspeed during climb
- conflicting data between pilot and co-pilot displays
- abnormal pitch and power combinations that don’t make sense
What causes them?
- pitot tube blockage (ice, insects, or debris)
- static port obstruction
- instrument failure or display malfunction
- electrical or data bus issues in modern glass cockpits
How do you handle it?
1. Recognize the mismatch
If the instruments don’t match the aircraft’s actual behavior, something’s wrong. Trust your instincts and cross-check.
2. Fly with pitch and power
Most aircraft have published pitch and power settings for safe flight configurations. Use these to maintain level flight, climb, or descent.
3. Disregard faulty data
Focus on the instruments you know are working—or fly using standby instruments.
4. Reference the QRH or abnormal procedures
Most airlines and aircraft types have a checklist for unreliable airspeed or instrument failures. Follow it step by step.
5. Communicate and coordinate
Share cockpit tasks. One pilot flies, the other troubleshoots. Stay calm, and talk through what you’re seeing.
Why this matters
Many accidents in aviation history—like Air France 447—were caused or made worse by unreliable indications that weren’t managed correctly. The difference between recovery and disaster is how quickly and confidently the crew switches from automation to basic flying.
Unreliable indications don’t mean the aircraft is lost. But it does mean you need to take over, fall back on fundamentals, and fly what you know. Pitch. Power. Trim. Communication.
The airplane doesn’t lie — just the instruments sometimes do.
