Fuel Gauges: Do they Indicate Properly

Fuel Gauges: Do they Indicate Properly?

by Tom Bennett, Civil Aviation Safety Inspector, Aircraft Maintenance and Manufacturing, Prairie and Northern Region, Civil Aviation, Transport Canada

There have been multiple incidents of fuel exhaustion over the past few years. In the last issue of the Aviation Safety Letter (ASL), you read about fuel starvation due to improper fuel selector condition. In this article, I would like to talk about another common factor in fuel starvation incidents: fuel gauges that do not indicate properly.

Some incidents were very public, whereas most incidents went unnoticed with the exception of being listed in the Civil Aviation Daily Occurrence Reporting System (CADORS). Some incidents were directly related to poor fuel management by the flight crew(s); however a few came as a surprise to the flight crew, as the fuel gauge(s) still indicated there was fuel in the tanks. An accurate reading of the fuel gauge may have prevented many of these occurrences.

There is some confusion about the need for serviceable fuel gauges. This confusion is especially prominent in the general aviation world. As both an aircraft maintenance and manufacturing inspector and an enforcement investigator, I have heard statements like: “The gauges have never worked properly. I just keep track of time in my tanks,” many times.

Such a statement is contrary to Canadian Aviation Regulation (CAR) 605.14(j)(i), which states: “No person shall conduct a take-off in a power-driven aircraft for the purpose of a day VFR flight unless it is equipped with a means for the flight crew, when seated at the flight controls to determine the fuel quantity in each main fuel tank […]”. This regulation is then carried through in sections 605.14, 605.15, 605.16 and 605.18 of the CARs, to apply to all power-driven aircraft in all nature of flights (day/night visual flight rules [VFR]/instrument flight rules [IFR]).

Furthermore, many aircraft must have their fuel gauges working as per their type certificates. For larger aircraft, especially transport category aircraft, the fuel gauges can be deferred by means of the minimum equipment list; however, this usually involves using other measuring devices installed on the aircraft and making complex calculations.

A common factor in fuel starvation incidents:
fuel gauges that do not indicate properly

Recently, a commercial pilot was fined because one of his fuel gauges was not working while he was operating an aircraft. In this case, as in others, the fuel exhaustion caused substantial damage to the aircraft during the forced landing. The pilot applied to the Transportation Appeal Tribunal of Canada (TATC) to seek relief from the $750. The TATC upheld the Minister’s decision.

The Aviation Enforcement Branch has also sanctioned aircraft owners and operators for unserviceable fuel gauges found during Transport Canada’s oversight activities. The maximum sanctions for an infraction under CAR 605.14, 605.15, and 605.16 are $3,000 for an individual and $15,000 for a corporation. The maximum sanctions for an infraction under CAR 605.18 (IFR) is $5,000 for an individual and $25,000 for a corporation. Inspection, maintenance and repair of a fuel indication system seem less costly, in my opinion.

Another common excuse I hear is that the gauges have always displayed faulty readings or they are too difficult or expensive to calibrate. As an aircraft owner, if you rely on this flawed thinking you are exposing yourself to numerous risks. First and foremost, you risk running out of fuel. This can lead to personal injury/fatality and damage/loss to the aircraft. Second, you are exposed to regulatory action by enforcement (fine or suspension). I think we can all agree that none of these are pleasant outcomes.

For the aircraft maintenance engineers (AME) in this scenario, I have not yet seen an inspection where the functionality of the fuel quantity indication system is not checked. Be careful what you sign for on the inspection forms and subsequently, the maintenance release. Following manufacturers’ instructions for inspection, maintenance and repairs will never lead you astray.

Most pilots and AMEs are aware that any accident or incident results from a series of events; there is never just one cause. Anything we can to do tighten up against the possibility of an error is a step in the right direction. 

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