Last year, I wrote about a Cessna 210 which suffered an engine failure while downwind at Bankstown Airport in New South Wales, Australia. I’ll quickly recap the controller and pilot interactions from the event which was the main information that we had.
At the time, I wrote that the pilot and one passenger were on a private flight from Camden to Bankstown in a Cessna 210 Centurion II. This was not quite correct but first, let’s take another look at the transcript and video.
They were approaching Bankstown when the first call was made on Bankstown Tower frequency.
Pilot of VH-MYW: Bankstown …Tower, MYW is approaching the [undecipherable]. The reservoir. Um, Echo… um, inbound, Cessna 210, two onboard, requesting permission to join.
Bankstown Tower: MYW: join downwind runway 29R, maintain 1,500.
Pilot of VH-MYW: Join 29R, maintain 1,500. MYW
Bankstown Tower: MYW: just confirm a downwind to runway 29R, maintain 1,500.
Pilot of VH-MYW: Um, downwind, MYW, runway 29R.
Bankstown Tower: MYW, Maintain 1,500
Bankstown Tower: MYW, confirm maintain 1,500.
Pilot of VH-MYW: Bankstown Tower, Mayday, Mayday. MAYDAY, MYW, engine, engine problem.
Once the engine failed, the pilot struggled to keep the Cessna’s altitude. At the same time, a news helicopter, also based at Bankstown but presumably already in the air, flew above the Cessna and began filming.
Bankstown Tower: MYW, roger. All runways will be available. Track as required.
The controller immediately made all runways available to the pilot, which means he’s now getting everyone out of the way.
Pilot of VH-MYW: Mayday, mayday mayday, coming in. Mayday, mayday.
Bankstown Tower: MYW, roger the mayday. We’ve got help coming your way.
Here’s the video taken by the news crew:
Bankstown Tower: Media 28, Bankstown Tower
This is the tower controller calling the news helicopter pilot.
Media 28: Tower, he is on the ground and uh, OK, he is sideways but he’s stopped moving. We are maintaining 1,500.
Bankstown Tower: Media 28, I’m not sure what your fuel status is but if able, request that you give us some more updates on that at 1,500.
Media 28: Well, technically, we are fairly low but I’ve got about ten litres. The aircraft is… is attended by people now and it looks like the pilot’s hopping out. I’ll get back to you in a bit.
Miraculously, the pilot and the passenger were unscathed.
On that day, the pilot believed that they had left with plenty of fuel for the short flight to Bankstown: sixty litres in the let tank and ninety litres in the right tank. They departed Maitland with no issues and continued to Bankstown. The pilot made a 25° banked left turn to join the circuit.
About two minutes later, As the pilot reported joining downwind, he felt a braking sensation and heard the propeller RPM increase. The engine was dead.
His recollection is that he changed the fuel tanks and quickly turned the electric fuel boost pump on and off again, with no effect. Unable to maintain altitude, he focused on maintaining the glide while looking for a safe place to land.
As a result, he did not work through the Engine Failure During Flight checklist.
- airspeed – 85 [kt indicated airspeed] KIAS
- fuel quantity – check
- fuel selector valve – fuller tank
- mixture – rich
- auxiliary fuel pump – on for 3-5 seconds with throttle ½ open; then off
- ignition switch – both (or start if propeller is stopped)
- throttle: advance slowly.
The pilot declared an emergency with a MAYDAY call. They couldn’t make it to the airport runway. Instead he aimed for the closest taxiway, leaving the flap retracted and gear up in order to reduce drag and gain maximum glide range.
Once he was sure he would make the taxiway, he lowered the gear, but there wasn’t enough time for the gear to lock into place before the aircraft touched down. The aircraft touched down wheels-up at the intersection of two taxiways and then skidded to the right, turning onto its side before coming to a halt.
The pilot and the passenger were uninjured. The aircraft sustained minor damage.
The investigation found no mechanical issues that could explain the engine failure. After the crash, they ran the engine on the fuel remaining in the tanks. The engine ran at low power with no issues.
However the fuel level was much less than the pilot had reported was in the aircraft, even taking into account that up to four litres had leaked from the one of the wings after the crash. The right wing tank was only a quarter full, with 40-50 litres in the tank, and the left wing tank held just 0-5 litres.
The pilot said he was carrying 150 litres of fuel, there should have been 61 litres in the right tank and 51 litres in the left tank. There’s no way that they went through 91 litres of fuel during a 35-minute flight and other than a small leak after impact (2-4 litres), there was no evidence of loss of fuel. Investigators concluded that the aircraft did not have 150 litres onboard at the start of the flight.
The Cessna 210 has a clever but complex fuel system. Each wing has a main tank which feeds into a smaller reservoir tank (just under 2 litres). The fuel selector valve has three positions: left, right and off, so only one tank can be used at a time. Each wing tank holds 171 litres, of which 169 litres is usable. However, when the fuel level drops to a quarter or less, any uncoordinated flight can cause the fuel to move away from these ports. Once that happens, only the small reservoir tank is feeding the engine, which Cessna’s testing showed would last only 1½ to 3½ minutes.
The actual fuel remaining in the aircraft was still enough to get them to Bankstown. The pilot said that the fuel was set to the left fuel tank on take-off, but about four minutes into the flight, they switched to the fuller right tank, thinking this would reduce the workload later in the flight.
From the pilot operating handbook:
Unusable fuel is at a minimum due to the design of the fuel system. However, when the fuel tanks are ¼ full or less, prolonged uncoordinated flight such as slips or skids can uncover the fuel tank outlets, causing fuel starvation and engine stoppage. Therefore, with low fuel reserves, do not allow the airplane to remain in uncoordinated flight for periods in excess of one minute.
Uncoordinated flight is when the aircraft skids or slips, most commonly in a turn. With a quarter tank or less, the fuel can drain away from the fuel pick-ups, leaving only the center tank fuel available.
That tank only has enough fuel to last a few minutes, which nicely explains how the engine failed two minutes after that 25° banked turn that the pilot made to join the circuit.
The Pilot Operating Handbook says:
If it is desired to completely exhaust a fuel tank quantity in flight, the auxiliary fuel pump will be needed to assist in restarting the engine when fuel exhaustion occurs.
With less than 5 litres in the left fuel tank, that left turn as they joined the circuit could easily have have disrupted the fuel flow to the engine. However, even if the pilot recalled correctly that they were set to the right tank, the levels were just low enough that uncoordinated flight could have caused the fuel in the right tank to flow away from the fuel pick-ups.
Either way: If the pilot had ensured that the fuel was set to the right tank and run the fuel pump for a few seconds longer, likely the engine would have relighted and allowed the aircraft to safely land on the runway.
That said, his focus was on getting the best glide from the aircraft. By keeping the gear up and the flaps retracted, he made it to the taxiway despite clipping the top of a tree. It is easy to see from the video that with even a small amount of drag during this time, he would not have been able to clear the buildings and the trees. As it was, both the pilot and the passenger were able to walk away.
However, this flight was under a flight permit meant only to relocate the aircraft for maintenance. There should not have been a passenger on board and the pilot should have been sure about the fuel amount in the aircraft, using a dipstick to confirm the amount of fuel in each tank.
The ATSB concluded that although the aircraft started with enough fuel to complete the flight, the low amount of useable fuel combined with the uncoordinated flight as they approached Bankstown led to fuel starvation as the cause of the crash.
You can read the full report at the ATSB website.
