Aircraft Owner with a CFI reported the aircraft ran out of fuel and the CFI landed the aircraft in a field with no damage. The owner used the incorrect fuel dip stick to check their fuel prior to departure.
Synopsis
Aircraft Owner with a CFI reported the aircraft ran out of fuel and the CFI landed the aircraft in a field with no damage. The owner used the incorrect fuel dip stick to check their fuel prior to departure.
Narrative
I am a CFI who was doing a high performance checkout for a new private pilot in his Aircraft X. The aircraft was low on fuel. We discussed getting fuel locally; however; the new fuel dipstick showed 21 gallons of fuel after 1.5 hours of flight. The planned flight was 40 minutes. About 60 miles around Class C. More than enough fuel. 5 minutes after takeoff; the annunciator indicated low on fuel in the left tank. I thought it was too sensitive since we had at least 19 gallons on board. 15 minutes later the Right tank annunciated low. I felt we had over 10 Gallons. Far more than an hour of fuel. As we descended from 3500 ft.; we discussed 'sticking' the tanks when we got there to find out how much fuel there really was. The engine stopped about 1500 ft. The owner flew the plane and I did the engine out drill. Best glide; landing field; and restart. No restart. The owner said 'you are more experienced; you have the airplane'. The landing in a field with low brush went well with no damage to the airplane. The new stick showed 0 fuel. When 5 gallons were put in each tank; the stick said 27 Gallons. This stick must have been for a different fuel configuration. The owner has ordered a new stick and it will be compared to the amounts of fuel as we put it in.
Second reporter narrative
I purchased a new gas dip stick for Aircraft X since the plane purchased in Date did not have one. Used it on several short trips measuring each trip against time in flight; then calculated gal per hour. Each trip averaged between 10.5 to 11.5 gallons per hour which is what on board fuel usages displayed so I had no reason to believe I had purchased incorrect fuel dip stick. On Date 1 in pre-flight I gauged both tanks (21 gallons) prior to departing for a short flight from ZZZ2 to ZZZ for training for high performance rating. Estimated 35 minutes depending on route. This met my personal minimum of 1 hour reserve. Approximately 30 minutes into our flight I started my descent. During descent I noticed on board gauges where showing low fuel and me and my CFI discussed the situation and then the engine quit. Picked a field and landed without any damage to plane; property or persons. Gauge tanks confirming both tanks where empty. Had a friend bring 10 gallons then checked again and tanks showed a total of 17 gallons on board. After inspecting the new fuel dip stick it read for use on bladder tanks only. Have ordered new dip stick and raised my minimums reserve on board to 2 plus hours.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.