Running Out of Gas: It Takes Focus

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While it might be true that fear is just fear, the kind that comes in knowing youíre running out of gas has a particular texture that seems uniquely capable of turning your brain to mush. I know this because like many pilots, Iíve had the experience of nearly running an engine on air. I could dance around it and say this ďhappenedĒ to me, but thatís a level of denial I just canít stomach. Like nearly everyone who runs out of gas or nearly does, I did it to myself.

I thought of this last week when reading about that Virgin-operated 737 that landed on a fogbound runway in Australia with just 15 minutes of fuel remaining. Ignoring the legalities and the reasons why that happened, I can tell you this: it takes no small degree of focus and deliberation to make things come out alright or at least survive it. The 737 crew had to land with near-zero visibility in an airplane and on a runway not equipped for that. Nothing quite centers the mind like having no choice.

It my case, I landed with about the same amount of time in the tanksóaround 15 minutes. I had taken our Mooney 231 up to central Georgia to cover Mauleís then-new diesel project. That 231 was relatively new to me and we were still wringing out the instrumentation, including a fuel totalizer. For the return trip, the totalizer indicated I could fly the leg with a little over an hour in reserve. Other than a forecast for scattered thunderstorm, the weather was good VFR and I got done late, so I just launched for Venice. I had a tailwind for part of it, a slight headwind for the rest.

Mooneys of that vintage are equipped with low-fuel warning lights which come on when the tank has about three gallons remaining. My habit was to run one tank about 10 minutes into the light then switch to the other tank. I like to have at least a dribble of gas in the empty tank in case the other tank wonít feed. About 40 miles out, the left light came on and 10 minutes later, I switched to the right tank and no sooner was my hand off the valve than the right light came on. What the hell? The totalizer said there should be almost 10 gallons in that tank. I thought to blame a fault in the low-fuel sensor, knowing full well the fault was probably between my ears.

By then, I was passing Sarasota, which was buried in a line of thunderstorms that ruled it out as a bolt hole. I was diverting over the gulf to get around them, adding yet more miles between me and homebase which was, fortunately, clear of weather. I throttled the engine back, leaned it as far as I could and pressed on. With the gauges on E and the bingo lights on, to say I was distracted during approach and landing is to abuse the meaning of the word. Mooneys have an Olympic-class ability to crow hop if landed too flat and too fast. I'm pretty sure I did both. But there was no way I was going around. It took most of the runway, but I got the airplane settled down and stopped. I wasnít exactly so much scared as feeling galactically stupid. This is where the focus and discipline comes in: the more important it is to get something right with only once chance to do it, the harder you try and the less likely you'll succeed.†

The harsh truth emerged at the fuel pit. As near as I could tell, the airplane had about 3.5 gallons remaining. What I discovered was in fueling this particular K model, full was not full. When the fuel was at the bottom of the filler neck, shaking the wings and letting the fuel settle would make room for another three-plus gallons per side. That accounted for about seven missing gallons the totalizer said I should have had. Iíd never run this airplane to its range limits and although Iíd flown plenty of 231s, I just never noticed this peculiarity, if indeed any had it. When I have a totalizer available, I like to run a tank dry and refill it to see what it actually holds, compared to what the instrument says the airplane is burning. But I just hadnít gotten around to that in this Mooney.

If I would have run it out of gas, it would have absolutely been fatal. I have multiple interlocking agreements with several friends that stipulate that if I ever run an airplane out of gas, they are to shoot me. Fortunately, the contracts didnít have to be executed and Iím trying real hard to make sure they never are.

Join the conversation. †Read others' comments and add your own.

Comments (16)

Hi Paul, my co-owner and I had a similar experience flying our M20k home to Danbury from Sun n Fun. We topped off at Keystone self service tanks about 7pm and I flew the final leg home. BTW I think the manual stated 8 gallons, 4 usable when the low fuel light comes on. Our top off procedure involved fill left, fill right, then refill left, and finally refill right. Our paper based fuel totalizer worked this way; takeoff and climb for the first hour on the left tank, second hour on the right tank, then burn the left until the low fuel light came on. Continue 20 minutes on the left tank then switch to the right tank. If you're not flying too high you should be able to calculate the remaining time remaining on the right, with a little reserve since the left tank inluded the climb. Well Paul, i can tell you if you fly straight and level, you can burn all 40 gallons regardless of what the manual says is usable fuel. I had told my copilot I was switching tanks, recorded it on the log, but never switched tanks. The fan quite abruptly about 10 miles past Salsbury MD. We decided we had enough excitement for one day and refueled at ILG, Wilmington, DE. Moral of the story, it may not be wise to start a long journey home after a full day in the hot FL sun. Regards, John, KCRG

Posted by: John McGlynn | July 22, 2013 5:58 AM    Report this comment

Sorry Paul, another point. In the M20K you should have a minimum of 9 gallons in the landing tank to avoid unporting the feed line in the event of a go-around.

Posted by: John McGlynn | July 22, 2013 6:02 AM    Report this comment

John, I know for a fact that almost every drop is usable in the tanks of the E-K Mooney models because I have done sealing work on them and probed around the intake port.

When we ran tanks dry for maintenance, they were dry enough to sop up what remained with a large rag. They will unport, I guess (never done it) but it must take work, given where the port is.

Posted by: Paul Bertorelli | July 22, 2013 6:23 AM    Report this comment

Another one that will get ya - breaking in a new cylinder and running full power to seat the rings. My normally 8 gph Lycoming went to somewhere near 13-15 gph when running rich at low altitude full power. Fortunately, I am a skeptical soul and did this while orbiting the airport just in case the new cylinder decided it didn't really want a to finish a career in airplane propulsion. The cylinder did OK, but I was shocked when I landed after 2 hours and had only a few cups of fuel left. Always leave yourself an out...

Posted by: A Richie | July 22, 2013 8:41 AM    Report this comment

This problem is certainly not limited to Mooneys. Both the running low, un-porting and usable fuel issues bit me doing pattern work in a Warrior. The book says 24 gallons usable, but the (not so) fine print says "in level flight". I can tell you that it's really 23.6 in a Vy climb attitude. In my situation, the combination of a busy day in the pattern and deferring the "fuel on fullest tank" item on the pre-landing checklist got me to the point in one tank where the remaining fuel sloshed into the back of the tank on the next takeoff and things suddenly got quiet at 200 AGL.

More recently I was ferrying a Sparrow Hawk back home after a day of instruction at an airport with very expensive gas and decided that 9 gallons was safe and legal for the 50nm flight. It would have been in a standard 152, but the Sparrow Hawk (with a 125HP engine) burns a bit more than 6 GPH.

Posted by: Jerry Plante | July 22, 2013 8:41 AM    Report this comment

I have maybe 150 hours of 231 time, but I never ran it low enough for the fuel lights to come on. That was the first airplane I had any experience in which had a fuel totalizer, and while I found it to be a fascinating addition, I didn't use it to stretch fuel.

I have stretched fuel too much twice, once in our 182 and once in our T210, back in my partner-ownership days.

The 182 event was stupid planning on my part, flying home to Laramie from a Midwest vacation with plans to refuel at Lincoln, NE, only to find that the FBO wasn't open 24 hours. By the time we landed at about 1 a.m. in Grand Island, which did have 24 hour operations, the Skylane took on 67 gallons--supposedly it had a 65 gallon usable fuel capacity. Dumb--really dumb.

In the T210, headwinds ate into the time enroute from Detroit to Denver, and it became obvious that it was going to be tight. I elected to run the right tank down to 1/4 and then run the left one dry, figuring that I'd then know for certain if Denver was possible, and if not, then land and take on fuel. That was the first and only time I ever ran a tank dry in any airplane, and the length of time as well as altitude loss that it took to restart the engine after switching convinced me not to do that again. We did land at Denver with about 10 gallons left, so perhaps not as dumb as the 182 incident, but dumb enough.

I now fly a much modified 63 P172D with a very accurate totalizer installed, not to stretch fuel, but to add some comfort compared to the wildly inaccurate fuel gauges. The longest leg in 9 1/2 years of ownership resulted in a 40 gallon refuel, with most other long flights approximating 36-37 gallons. That usually stretches my own endurance. Although perhaps not as necessary as in the 231 or the bladder-equipped 182, I make a point of shaking the wings to insure a complete fill-up, and it does make a difference of maybe a gallon or so per side--mostly dihedral and the inboard location of the fuel fill traps air in the tank, and rocking it allows some of that air to escape.

I don't have anyone programmed to shoot me if I run out of fuel, but I don't intend for that to happen, either. Two dumb fuel-related events in a lifetime of flying are two too many.

Cary

Posted by: Cary Alburn | July 22, 2013 8:53 AM    Report this comment

It isn't just sketchy math or fuel totalizers that can get you, sometimes it mechanics. I had just purchased a Cessna 421C and was flying it home from Long Beach CA to Toronto, Canada. The aircraft was equipped with two long range fuel tanks in the wing lockers. The procedure is to use enough fuel from the mains, then turn on the transfer pumps of the Aux fuel tanks to pump the fuel directly into the mains. A short time out of Long Beach, after burning some fuel, I tested the transfer pumps and both pumps seemed to be working fine as indicate by the light above each switch.

I was expecting to make my overnight in Denver from Long beach and somewhere over Las Vegas I had burned sufficient fuel from the mains to allow enough room for the fuel transfer. I flipped the transfer pump switches and was looking forward to watching both my fuel gauges magically rise. After a few seconds the left transfer pumps quit and wouldn't re-start. I had less than half a main tank in the left, and a full main in the right.

I wasn't pleased but not worried as I had more than enough fuel to make Denver, or so I thought.

I soon realized that I would need to cross feed the fuel on the right. If I kept flying I would use all the fuel in the left main, leaving me half a tank in the right, so I engaged the cross feed valve to run both engines off the right tank. When the tank would indicate the same quantity as the left side, I would switch the cross feed back to "both" and the plane would be balanced.

Somewhere over the Rockies, the tanks evened out and I spun the fuel selector back to both. I say spun because that's exactly what the selector did, it spun freely. No amount of fiddling would get it to engage, plus I worried that if I kept trying to move it, I might get it stuck out in a null position and that would be disastrous.

My only landing option was Grand Junction CO and by my calculations it was going to be really close. I was now committed to flying and landing the aircraft in cross feed and running the useable tank to almost empty. I started to imagine how the post mortem article would read if I crashed. "Stupid pilot runs out of fuel with full aux tank and half a main tank of gas in the airplane".

By the time I arrived at Grand Junction the right gauge was sitting on empty and the fuel imbalance was hard to hold. I kept turns to a minimum in case the fuel became unported on the right side. There was no go around in my plan, this was a one shot deal. I kept the approach high to maximize the glide distance and we landed safely.

I had the selector repaired and when we refueled the aircraft, the right main had only 10 gallons left in it, which after deducting unuseable fuel, amounted to about about eight minutes of flight.

So sometimes you can run out of fuel even when there's lots on board.

Posted by: James Kabrajee | July 22, 2013 10:57 AM    Report this comment

It's always frustrating to read about pilots bending perfectly good airplanes because they ran tanks dry. Years ago I ferried a gentleman's Baron from CT to FL as he was recovering from an airplane accident. He had flown a King Air from Miami to Venezuela, and had made the trip on a few occasions so he knew the plane was capable of finishing the leg. Turns out it was at the ragged edge of the plane's range. He topped off and departed, only to have the engines flame out on approach to the runway at his destination. The plane crashed 1/2 mile short, severely injuring him and his friend and killing his friend's son. When he told me the details, he made it sound as if the fueler was responsible because he didn't top the tanks in proper sequence and therefore the tanks weren't completely full. My thought was if just a few gallons would have meant the difference between landing and crashing, then he had no business trying to push the plane to its limits. (never mind the required VFR fuel reserves) Of all the things in aviation that we have no control over, having enough fuel on board for the flight is one thing that pilots do have control over.

Posted by: Will Alibrandi | July 22, 2013 12:33 PM    Report this comment

Rare is the pilot with more than a few years in the logbook who hasn't at some point flown a bird at least to the point of being "deeply concerned" about fuel state.

I know in my case just such an incident has led to a lot of unnecessary "tankering" of fuel, a totalizer full tanks setting about 4 gallons shy of actual capacity, and habitual padding of consumption estimates. Plus a co-pilot who watches the process like a hawk. Hopefully it will all be enough to prevent a future recurrence.

Posted by: John Wilson | July 22, 2013 4:05 PM    Report this comment

Two thoughts:

I sold an EAA Biplane - the kind with a cork-and-wire "fuel gauge" - that was lost when it "probably" ran out of fuel on lift off after a touch-an-go in the local pattern. I suspect that wouldn't have happened had the pilot considered that pitch attitude on lift-off has a critical effect on the "apparent" fuel on board.

I had a close call a few years earlier when I elected to go around in a C-120 with "adequate" fuel on board. Pitch attitude is CRITICAL in light aircraft when low on fuel.

H2

Posted by: Unknown | July 22, 2013 5:24 PM    Report this comment

Arriving at Class D - HFD - Hartford and getting close to only 30 mins usable in the tanks after a VFR day kicking around the block I was nicely on final when the plane in front of me didn't clear the runway. I was already going around when tower called it and then something inside twitched. The pattern was busy and I could see I was going to get slotted in at number 4 or 5. It wasn't selfishness but self preservation had me make a "minimum fuel" call. There was a slight tone of disbelief in the tower's response but they adjusted the pattern and put me in at No 1. With that twitch really twitching I flew a very tight 500ft AGL and power off 180 pattern. I taxied in to the pumps. There should have been around 6 galls in the tank (3 effectively unusable in the 150). There was just over 3. Somewhere during the day I must have flown a leg full rich or something similarly stupid. In any event I now have a personal minimum of 1 hour usable day VFR. And 600 hours later in that plane I have never had a surprise like that at the pumps again. Never ignore the "twitch".

Posted by: Graeme Smith | July 23, 2013 5:53 AM    Report this comment

My uncle used to say "It costs the same to keep the upper half of the tank full as it does the lower half" ....ha ha!

Posted by: A Richie | July 23, 2013 9:54 AM    Report this comment

How many of life's important moments involve performing when you know you've screwed up? I can think of a few. When I was a kid, I'm sure it lowered my performance, thinking about how much trouble I was going to be in. As an adult, I reckon I'm better at focusing on the job at hand and worrying about the consequences later. That's my theory anyway. It certainly is one way to sharpen the senses.

Posted by: John Hogan | July 24, 2013 8:34 AM    Report this comment

Last fall, I installed a new digital fuel gauge system that is calibrated by the gallon in my 172. Previously, I timed my flight to estimate my fuel burn - my plan was 3 hour legs, at 3.75 hours I had to be on the ground, I should have 1 hour of fuel remaining. At any rate, we returned home from Baltimore last New Year's eve, and pushed our range out to 4 hours on the return flight home. I did a visual & dipstick check of the fuel tanks - this confirmed I had a good 45 minutes reserve upon landing and put the plane in the hangar. I noticed a puddle under the airplane a few days later (and no fuel in the tanks) Turns out the fuel selector developed a leak sometime after parking the airplane and drained out all of my fuel.

Lesson: A fuel totalizer, or stopwatch only tells part of the story. If you develop a leak in flight, or leave a fuel cap off, all bets are off on the totalizer. An ACCURATE fuel level gauge is essential to back up the totalizer.

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