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After 3 years 1 month and 8 days since the accident the NTSB finally released the final report on the accident that occurred north of Chicago in July 2019. https://data.ntsb.gov/carol-repgen/a...port/99827/pdf

Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:

• The pilot’s decision to operate the engine above its maximum continuous speed for most of theflight, which led to fuel exhaustion and a subsequent total loss of engine power.

There is a bit to digest in there but the bottom line is at lower density altitudes it is possible to cruise above the maximum continuous engine speed of 5,500RPM, you should not do this for more than 5 min according to Rotax and the A5 POH.

If you fly at greater than 5500 RPM

• You are not on the charts anymore so nothing they say can be used.
• The fuel flow will not be what's in the POH performance charts it can be substantially higher.

It is possible to cruise at full throttle between 4500-5500RPM at higher altitudes the performance charts are good as long as you are between 4500-5500 RPM!

This pilot planned a flight using fuel flows in the POH but then flew well beyond the conditions that he planned and that are in the POH for well over half the flight. There were even times where they flew at or above 5,800 RPM on the engine. Also note that his wife nearly almost ran out gas too. Most people that have ever flown significant formation will tell you trail will ALWAYS burn more fuel trying to keep up, lead always needs to fly a bit slower so everyone else can keep up.

There are two fuel indicators on your planes. One is a float style that tells you what's in the the tank in 1 gallon increments. There is a completely separate low level sensor that is independent of the normal fuel indicator and it lights up as a red LED in indicator display. If you see that light in level flight you have 2 gallons or less of fuel on board most of which is usable but still that is really really low on fuel.

Be safe out there.

Bret

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Bret thanks for sharing. The NTSB stated:

"The manual notes that the switchover between the economy and power modes occurs when the throttle position is advanced above 97%. In economy mode, the expected fuel consumption rate is about 4.8 gallons per hour at 5,500 rpm and a manifold pressure of 27 inches of mercury. In power mode, the expected fuel consumption rate is about 6.9 and 7.3 gallons per hour at 5,500 and 5,800 rpm, respectively."

I can't find any reference to this in the POH. Looking at the cruise perfomance chart I just see substantially higher FF at 5,500 rpm.

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The language they are referencing is in Rotax 912iS Operators manual (page 5-5). Its not referenced in the ICON A5 POH as it inconsequential information as long as you are operating between 4500 and 5500 RPM the increased fuel flow at operations above 97% throttle is taken into account in the performance charts. The problem is when people cruise above 5500RPM. Most A5's don't have a display that can indicate throttle % but the G3X equipped aircraft the throttle % is indicated on the display before start if I remember correctly.