Safety Alert Calibrated Dipsticks

The use of a calibrated dipstick is great way to check fuel on board your aircraft unless it is calibrated for a different aircraft or fuel tank configuration then all bets are off. You may easily be misled into making a critical mistake.

The pilot of a Cessna 182 made a perfect forced landing on a road after the engine stopped due to fuel exhaustion. There was no damage to the aircraft and no injuries.

The fuel gauges showed a total of 50 gallons usable. The estimated time enroute was 2.5 hours with fuel burn was calculated at 12.6 gallons per hour. This should have provided adequate fuel for the flight and sufficient VFR reserves.

According to the pilot, at the time the engine stopped, the gauges showed between 5 and 10 gallons per side. The Hobbs time showed 2.7 hours and the tanks were completely dry. A fuel truck put 10 gallons in each side but the dipstick read 17 gallons per side or 14 gallons more than was put in the plane.

Recalculating the original fuel load, the pilot determined that instead of having 50 gallons usable when he started the flight, there was only 36 gallons aboard - a fact borne out by the time from departure to forced landing.

The pilot said this dipstick was calibrated for a Cessna 182 with bladder tanks and if used on a later wet wing Cessna 182 will result in a fuel shortage. He also stated that he had received no manufacturer's alert bulletin or disclaimer to alert Cessna 182 owners and operators.

The obvious lesson is that fuel dipsticks must be calibrated for the appropriate model and tank configuration. The fact that it says " Blue Streak 200" on the stick does NOT mean that it will be accurate for your aircraft unless you know the tank configuration. It is essential to verify the accuracy of the markings.

This source of this alert was the NASA ASRS.