The good news first - we didn't run out of fuel. The background to this hinges on the use of old kit, not specific to the aircraft i.e., a fuel dip to show how much fuel was in each tank on a Cessna 182.

1. Situation

Our mission was to collect a new Cirrus SR22 at Gloucester Airport. An instructor and qualified Cirrus pilot accompanied me to Gloucester so they could fly the Cirrus back to our home base, and I would fly the Cessna 182 myself so I could start training to convert to the Cirrus.

2. Task

The Cessna 182 was fuelled but below tabs, and the fuel bowser was inoperative that morning, so we were tasked with ensuring the fuel calculations were appropriate for the return journey, especially as Gloucester also reported fuel was not available that day.

The fuel dip showed we had 30 USG of fuel on board (approx. 15 per wing). We needed a total of 16 USG.

Therefore we started our journey with confidence that we could return safely, needing no more fuel.

3. Action

We took off, arrived at Gloucester and checked out the new Cirrus SR22 without any issues.

All good so far...Rechecking the fuel quantity, we had used the planned 8 USG, so had 22 remaining.

On starting the Cessna 182, the fuel light momentarilly illuminated but went off again, so we continued our checklist tasks and finished with the pre-departure power checks - no fuel light, so we took off when cleared. 2 mins into the climbout, the fuel light illuminated but remained on this time.

As a result, we began to plan for scenarios just in case the fuel calculations were made in error or the quantity was less than we thought. This included identifying airports on route which we knew had fuel, as well as switching tanks so that, in the event of the fuel running out on that tank, we would still have a few mins in reserve in the original tank.

On route, the engine began running rough so we switched tanks and recalculated the time remaining to base and the closest alternate. As we were only 10 mins away, we continued and landed safely.

On arrival, we rechecked the fuel level and the left tank was empty, and the right tank had a very small amount (well below the 5 USG mark. We filed a report with the head of safety to investigate, as we wondered if the fuel dip was incorrect on our departure and at Gloucester.

4. Result

On investigation, the fuel dip was found to be for a different aircraft, but had been in use for an extended period in the Cessna 182. This meant the initial pre-departure indication was a gross over-estimate, and was actually likely to be around 20 USG, not 30.

In practice, despite one tank being depleted, there was sufficient plus a small reserve of around 20 mins when we departed Gloucester.

However, if there were a delay by ATC or other problem on route, it could have meant running out of fuel entirely.

The lesson learned by everyone involved, was to make certian that any equipment used is definitely appropriate for the aircraft before relying on any measurements. Also that 'get-there-itis' (the strong desire to get to the destination at any cost) is a risk for us all that we must be aware of.

The trip could have been deferred to another week at least, so fuel at one or both ends were available which, with the benefit of hind-sight, would have been the right thing to do. Procedures were changed at the home base for any such eventuality in future.

Thankfully no such event has been repeated since, so the safety process has been effective.

Please do ask us for more insights and we will be happy to discuss the case and any of your experience to help others.