What it Looks Like - Aircraft Fuel Sender - Mark Twombly AOPA

What It Looks Like Fuel sender - Variable Potentiometer  By Mark Twombly How do you know with confidence how much fuel is in the tanks when you taxi for takeoff? The same way you do in your car: Check the fuel quantity indicators. As every new pilot eventually comes to realize, however, fuel quantity indicators in the typical light aircraft are notoriously inaccurate except, perhaps, when they read Empty. Fuel quantity needles bounce in turbulence, often lag in indicating a depleting supply of fuel, and then seem to speed up their descent as they near the big E. This is why we visually check the fuel quantity as part of our preflight inspection. A big reason for the temperamental behavior of analog fuel quantity gauges is the fuel sender, the mechanism buried within the fuel tank that measures fuel level. Although there are several different types of analog and digital fuel senders, the type found in most light single-engine aircraft is based on a simple float system. The lightweight float is attached to one end of a thin metal arm, the other end of which pivots inside a sealed housing. The housing, which is submerged in the fuel, contains a resistance element and contact system. The float arm contacts a coil or winding inside the housing that is energized with current sent from the fuel quantity indicator on the instrument panel. Different positions on the winding represent different resistance levels. As fuel is consumed and the float descends in the tank, the float arm contact slowly moves along the winding, gradually changing the resistance in the current read by the gauge. The current reading is translated into an analog needle indication. So what happens if the electrical current somehow shorts and "leaks" into the fuel tank? No worries -- the current is too weak to ignite the fuel or even fuel vapors. One manufacturer of resistance type float fuel senders says the design life is 100,000 empty-full-empty cycles but includes this important caveat: "Actual service life may be less because of wear caused by vibration and fuel movement." Add to that the ravages of time and infrequent use that no doubt accelerate the aging process of a fuel sender . So, along with learning to take off with sufficient fuel in the tanks to complete the intended mission plus some, we soon learn to treat fuel gauges with a healthy skepticism. The best bet is to back up the fuel quantity indicators with another simple measuring device: a watch.

Press Release - TSO Granted - AOPA Summit

NEWS RELEASE                                    FOR IMMEDIATE RELEASE

CIES Corporation receives FAA TSO approval for new digital fuel level senders

October 10, 2012, CIES Corporation of Redmond, Oregon has received FAA TSO C55a approval for its line of digital fuel level senders. The float based fuel level senders are designed to replace the majority of the existing fuel level sending systems in general aviation aircraft. The proprietary and patented system provides a new level of accuracy, reliability, and stability to fuel level indication in the cockpit. CIES meets a TSO standard of 2% variance in tank volume, a standard normally reserved for corporate and commercial aircraft with corrected capacitive solutions. No other float based system meets this stringent TSO standard while achieving the intrinsically safe (i.e. “no wires in the tank”) requirement.

Richard Kirkness, Vice President of CIES said, "As a manufacturer of aircraft systems, we see FAA certification as critical to our success and the foundation for everything we do. FAA approval is the result of months of hard work on the part of our team here in Redmond and could not have come at a better time for CIES as the company continues to grow and strives to achieve the goal of becoming a world class supplier of advanced systems and technologies.”

Charlie Babb, General Manager of CIES added, “After the successful introduction at the beginning of this year of our senders on all new Cirrus production aircraft, we began working with other manufacturers and owners groups to provide specific fuel level sending solutions for production and legacy aircraft. The next logical step was to acquire FAA certification to validate our quality control system and lean manufacturing processes while making aircraft integration and approval significantly easier to obtain.”

The CIES fuel level senders require a dedicated digital fuel level display to ensure that the 2% accuracy achieved in the fuel tank is provided in the cockpit as well. As a result, CIES partnered with Aerospace Logic in Hamilton, Ontario to utilize their digital fuel level cockpit display. Aerospace Logic updated their fuel level gauging system to accept the digital communication link from the CIES digital senders.

CIES Corporation of Redmond, Oregon USA provides a range of high-technology products and support services to aviation, aerospace, and the broader transportation marketplaces.

For additional information on CIES and its products please visit the CIES Inc Website

For additional information on Aerospace Logic and its products please visit the Aerospace Logic Website

Fuel Management

Fuel Management

“From an accident prevention perspective, fuel mismanagement is one of the most frustrating problems. The accidents are easy to avoid. The hardpart is reaching the pilots who are most at risk, because they’re not the ones attending safety seminars or taking online courses. A new approach is needed to get pilots to stop and think about the issue. Airing some ‘dirty laundry’? Perhaps, but we think it’s more than justified by the lives, aircraft, and dollars we lose to this problem every year. 

ACCIDENTS do far more damage to GA’s reputation than educational efforts to rectify the situation.

It shows that, the pilot community,  is making a good faith effort to address the problem.”

—Bruce Landsberg, President, AOPA Foundation

Fuel Management Accidents

Fuel management accidents are among the most preventable types of GA mishaps, and yet pilots still manage to turn perfectly good airplanes into impromptu gliders at an alarming rate well over two per week in the US.

The primary way GA pilots manage fuel on board is to do arithmetic.



 You look at the length of your trip, the winds, read some performance charts, then bust out your calculator or whiz wheel  to figure out how long it will take you to get to your destination at what fuel burn. I might get anywhere from 10 to 18 miles per gallon on a flight. And if the headwind is stronger than I expected or I'm routed the long way, it might take more than that. The 30 minute required reserve  is really not enough. 

FAR Part 91-151