Aircraft Fuel Management - Down Under - Civil Aviation Authority

Sometimes it's helpful to look at how other countries address a similar problem.  The below excerpts come from the New Zealand Civil Aviation Authority.

Determining Fuel Available

Accurately determining what quantity of fuel you have on board is important. Assuming the fuel required for the flight has been calculated correctly, it should be a simple matter of uplifting it and completing the flight with a comfortable margin to spare.

It is good practice to check the fuel available before flight by at least two separate methods (in Australia, this is a legal requirement). We can do this by referring to the fuel gauge(s), loading a known quantity and, in many aircraft, by dipping the tanks. There are a number of considerations that should be borne in mind when determining the fuel available.

Unusable/Usable Fuel

Understanding the difference between the terms usable and unusable fuel is important in determining the fuel available for flight.

The unusable fuel is the quantity of fuel that cannot be used in level flight. It is the quantity remaining in each tank after the tank outlet becomes uncovered in level and balanced flight. The amount of unusable fuel can vary considerably from aircraft type to aircraft type – refer to your aircraft Flight Manual for specific figures. The fuel tank outlets on some aircraft types are very susceptible to becoming un-ported during prolonged unbalanced flight, which eventually leads to fuel starvation and engine failure.

Extreme care must be taken to ensure that the unusable fuel quantity is not included in the fuel available, as it can equate to as much as 20 minutes extra flying time that you don’t actually have.

It follows that the usable fuel is the quantity of fuel available for flight planning purposes. This is the only figure that should be used when calculating fuel endurance. Most dipsticks are calibrated to read the total fuel quantity in the tank, which means that the unusable fuel must be subtracted to determine the fuel available for flight. Care must be taken when converting between litres, and US or imperial gallons. Calculations should always be double-checked.

Fuel Gauges

Most fuel gauges read reasonably accurately, and if they don’t, they must be fixed. Gauge accuracy can easily be checked before the flight by dipping the tanks (if that is possible) and comparing the figures with the actual gauge readings. Any discrepancies must be allowed for until the problem can be fixed.

Be aware that fuel gauges can stick or fail in flight, sometimes in a subtle way, so don’t rely on higher-than-expected readings which seem at odds with expected consumption as the flight progresses. Also, in some common aircraft types, fuel gauge indications will vary widely according to the direction and degree of any slip or skid.

Some aircraft have tank designs where a dipstick reading can’t be obtained at certain fuel levels, so the use and accuracy of the fuel gauges becomes even more important to the pilot.

Don’t Blame your Fuel Gauge

"According to the Joseph T. Nall report (produced by AOPA’s Air Safety Institute), 89 accidents occurred in 2010 as a result of fuel exhaustion; 11 of them fatal. And despite a decline in fuel management accidents through 2008, more recently those numbers have been reversing, accounting for eight percent of all accidents in 2010.
According to the Nall report, inadequate flight planning — failure to determine the amount of fuel required for the flight or the amount actually on board, or to verify the rate of fuel consumption en route — accounted for the largest share (48 percent)."

This was reported below in the FAA Safety Team Briefing in October 2013 and is indented in italics:

FAASafety

Briefing - Fuel Monitoring 

October 2013

The General Aviation Joint Steering Committee

Safety Enhancement Topic of the Month

Don’t Be “Fuel-ish”

While fuel exhaustion continues to be a a top ten issue for General Aviation safety - It gets very little insight or a real root cause analysis to the factors involved.  To most in the aviation field this is a simple pilot problem with a very simple answer, But there is a hidden truth lying in the commonly held belief below:  

"One of the more head-scratching aspects of fuel management accidents is simply how easy they are to prevent, as well as recognize well before they happen.Blaming a bad fuel gauge doesn’t cut it. To help prevent getting into this situation, here are some tips:"

Note:  A fuel gauge is required equipment on all powered GA aircraft and it is supposed to be accurate throughout the range from empty to the zero fuel level.  

The FAA Safety Team implies in the paragraph above that you could be flying your aircraft with a bad fuel gauge - I hope this isn't so.

§91.7   Civil aircraft airworthiness.
(a) No person may operate a civil aircraft unless it is in an airworthy condition.
(b) The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight.  The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.

§23.1305   Powerplant instruments.
The following are required powerplant instruments:
(a) For all airplanes. (1) A fuel quantity indicator for each fuel tank, installed in accordance with §23.1337(b).

§23.1301 (Systems and Equipment) Function and installation.
Each item of installed equipment must—(a) Be of a kind and design appropriate to its intended function.(b) Be labeled as to its identification,function, or operating limitations, orany applicable combination of these factors;(c) Be installed according to limitations specified for that equipment; and (d) Function properly when installed.

§23.1337   Powerplant instruments installation.
(b) Fuel quantity indication. There must be a means to indicate to the flightcrew members the quantity of usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to indicate those units must be used. In addition:
(1) Each fuel quantity indicator must be calibrated to read “zero” during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply determined under §23.959(a)

And this is where the hidden truth lies,  and this is where I believe the  FAA Safety Team author missed the point - It is a subtle but significant difference and it should read as follows:

Flying an aircraft with a bad fuel gauge doesn't cut it 

If we review  -  I believe the accident chain starts at this point.

• After visually checking the fuel in the aircraft,  the pilot then got into the aircraft   put power onto the aircraft and observed that the fuel gauges did not report accurately how much fuel was in the tank.  

Or 

• The pilot observed on filling the aircraft that the gauges indicated the aircraft had more or less fuel than that required to fill to tabs as an example.

STOP RIGHT THERE - Take your aircraft to the nearest service center and have your required aircraft equipment repaired or replaced to make your aircraft airworthy.  

Don't fly an aircraft with bad fuel gauges - it is that simple.

If you are flying an aircraft with bad fuel gauges - you should have a ferry permit.     

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When you look at it from this perspective - yes the solution to fuel exhaustion may be just as easy as the brief author suggests.  

Simply mandate that required fuel level reporting equipment function properly when installed on the aircraft.  

I understand fuel level reporting is not good in GA - That they don't work is the universal complaint.  

If that is true, then this problem lies with the FAA Administrator -

1.) Did the FAA Administrator allow an Aircraft Type Certificate to be issued that ignored fuel level reporting requirements of FAR 23.1301, FAR 23.1305 and FAR 23.1337.

2.) Does the FAA enforce the requirement that this equipment is to function     throughout the life of the aircraft as designed above.

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Why have we turned a blind eye to fuel level equipment & why are fuel reporting systems treated in a different manner than any other required equipment on the aircraft. 

Because if we re-write the FAA Safety Brief and replace fuel level with another piece of required equipment ..... Frankly, it just sounds silly.   

"One of the more head-scratching aspects of airspeed management accidents is simply how easy they are to prevent, as well as recognize well before they happen.Blaming a bad airspeed indicator doesn’t cut it. To help prevent getting into this situation, here are some tips:"

Required equipment is required for a reason - let's make it that way.