Why Are Legacy Aircraft Fuel Gauges Notoriously Inaccurate?

Answer can be traced to a combination of multiple things—corrosion, latency, and time.

FLYING Staff

Wednesday, December 11, 2024 at 11:02 AM ET

Verified

Edited By: tccjeremy

Key Takeaways:

Legacy aircraft fuel gauges are notoriously inaccurate due to a combination of corrosion (from moisture and dissimilar metals), wear exacerbated by periods of stagnation, and abrupt movements during flight.
This inaccuracy leads to false fuel level indications, contributing significantly to fuel starvation accidents, which are a leading cause of incidents.
Upgrading legacy aircraft with modern, high-tech, corrosion-resistant digital fuel level sensors and compatible digital gauges is highly recommended as a critical safety improvement.

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Question: Why are legacy aircraft fuel gauges notoriously inaccurate?

Answer: It is the combination of multiple things—corrosion, latency, and time.

There is always trace amounts of moisture in fuel, and it produces compounds that are corrosive. While most of the aircraft is aluminum (which is lighter and less susceptible to corrosion), steel is used in specific applications (such as older fuel senders) because of its conductive qualities and low cost.