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Fuel Exhaustion (long but valuable)

tkatc

Well Known Member
Exhaustion/starvation is the leading cause of aircraft accidents/incidents. This is an audio clip of the actual controller trying to help me after I possibly made my last mistake. He did a great job along with a Spirit pilot trying to help as well. Everyone involved did a great job trying to make the best of a bad situation. I have a lot of people to thank and a lot to be thankful for.

This incident is a serious embarrassment and blow to my ego. It has taken me awhile to get over it but now that I have, I hope to educate other pilots so they do not find themselves in a similar situation. Before I begin, some background information is needed. I am a controller by profession and was recieving VFR advisories from the facility where I work as I was flying from one small airport to my home airport on an overcast November afternoon. (the day before Thanksgiving) The final leg of this day would be a short 20 minute flight.

That morning I did a normal pre-flight. I physically checked the tanks and they were both full. The fuel guages were not accurate and as such I did not use them. I based all my calculations off of the hobbs meter. I had been in the market to purchase my own airplane and in my search I ran across many advertisements that read "Cruises at 8 gph", many said similar things ranging from 6-9 gph. Occasionally I would come across an extremely thirsty plane that consumed 9.5 gph. I had trained in a C-152 that burned 5.5 gph and on this day I was flying a C-172 which I assume would never burn more than 10 gph. I figured that was a very safe estimate but obviosuly I figured wrong.

I took off from my home base in NJ to visit a friend in PA. About an hour flight. We hung out for a bit and then off I went back home. I had tentative plans to take a skydiving buddy of mine up for a local flight and when I arrived back home I called him and he said he was on his way. He explained he would be there in 20 minutes and asked if it would be ok to take his 14 yo nephew. I said "Sure", I wasn't fortunate enough to get many opportunities in my life, so I was always willing to supply a few when I could.

As I waited on my friend I figured I would fuel up and looked over towards the pump and discovered another airplane just pulling up for fuel. "Oh well" I thought, I have plenty of gas. There is only 2 hours out and should have at least 2.5 more hours.

My buddy and his nephew arrived and we took off for a local airport for lunch. It was a 25 minute flight. Unfortunately, the grill was closed for remodeling. Off we went to another local airport. We flew over the airport I work and decided to do a touch and go enroute. Then off to the destination airport. That flight took about 35 mintutes. We landed and had lunch. It was a great day and the 14 yo who had been nervous about his first GA flying experience was getting comfortable and decided to sit up front for our last leg home.

As we approach the plane my buddy asks me if I want him to check the tanks. I declined the offer and just rechecked the dispatch sheet and hobbs meter...the plane was only out a mere 3 hours. Surely I had enough fuel for the 20 minute flight home with 30-45 mintues of reserve.

We take off and I immediately acquire advisory service from the approach control where I work. Ten minutes into the flight...then engine sputtered and quit immediately. The following audio clip will explain the rest. It's slow at first but will have some highlights that may hit home and help you to avoid a similar mistake. http://www.vimeo.com/13290059

As you can see, this was a typical accident where a chain of events lead to this potential disaster. If I had broken any of those links this might not have happened.

As I said, I am extremely embarrassed to make such a mistake. At the same time I am extremely proud of the fact that I did not give up...I did not panic...I flew the plane until it would not fly anymore. It was hard enough to maintain composure but it was tougher when the 14 yo was crying out that he "wanted to see his mom again" and "he didn't want to die". (He is now a big 6'4" teenager that would never admit to this but I think he did a great job anyway) I knew my buddy would keep his cool because we have been in extreme situations with each other before. (we are skydivers) I told my friend to tighten up all the belts. We weren't going to make the open field off in the distance.

When the engine quits it is very quiet up there. 2 minutes and 21 seconds doesn't sound like a lot of time but it is forever when you are looking into the face of death. A non-moving prop looks very eerie. I remember at one point I tried to restart the engine and the battery was turning the prop over, for a split second I was pleased to see the prop turning over thinking it would actually propel me enough to make a nearby field. (Your survival instinct will play tricks on the brain sometimes) When we were coming into the treetops it sounded like an aluminum canoe slapping into some choppy waves. I flared as if I were going to land ON the treetops. This had us at a very slow speed. Soon after I had no control as the plane bounced off of several trees but I STILL tried to manuever. We came to a stop and we all got out without a scratch. The first thing I did was check the tanks for fuel...I was still in disbelief. On this day the C-172 burned 13.9 gph. A far cry from the 10 I assumed would be a lot.

A few lessons learned....

Never stop flying the airplane...NEVER.

Altitude affords you more options. I was at 2500' and was able to glide about 2.2 miles.

Don't immediately go to flaps...without flaps I could have glided another 500 yards or so and would have made my intended field.

Renters insurance is a must!! ; )

I am glad to have overcome this incident and I was grateful that most of the comments I heard soon after the incident were positive. I have since heard all the comments, good and bad, and my ego can now handle it. My skydiving buddies actually got me a copy of Jackson Brown's "Running on empty" for Christmas.
Flame me if you'd like. Dismiss this as a mistake you would never make. Just make sure YOU NEVER MAKE THIS MISTAKE!!!!
 
You have a lot of guts!

You have a lot of guts! NOT FOR THE FLYING BUT FOR THE POST. I DON'T KNOW IF THIS IS AN IMAGINARY EVENT INTENDED TO TEACH OTHERS OR IF IT REALLY HAPPENED. TOTYCHTMGIIYAOF!

Bob Axsom
 
Very noble of you to put this out here. "There for but the grace of God go I" will most likely ring true for a number of pilots in this community. Great job of flying the airplane all the way to the end. It always makes a huge difference in the outcome. Hopefully, you will recover from this, both mentally and financially, and keep flying. The only pilots who haven't made any mistakes are those who haven't flown yet. Some mistakes are little and come with minor consequences, and some are far more critical. I am sure this episode should make you a VERY careful pilot for the rest of your flying days.

Vic
 
TOTYCHTMGIIYAOF??

Yes...it is very real. It took me a few years to come to grips with this. there is NOTHING good about this event....UNLESS it helps somebody else avoid this in the future.

I would have been flying an RV by now had it not been for this. As you can hear...I sounded very scared....and the controller was a bit shaken too. A story of a lifetime eh?
 
You are to be commended for telling your story so others may learn and live.

Lesson learned!

Thank you!
 
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Very sobering. Thanks for sharing this difficult event with us - a great learning experience. And good job keeping the plane under control as long as possible.

erich
 
Other than running out of fuel, is there anything you would have done different? I know you have replayed this event in your mind 1,000's of times. Any thing you can think of that you could have done better?

This is a very interesting thread to me. How anyone reacts under pressure, in an emergency, is always the unknown factor.
 
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Very glad you had the guts to post this. A lesson for the rest of us.

Could have been any of us!
 
That post requires some guts.....thanks so much for sharing. Don't know why anyone would flame you for fessing up and admitting your mistake.

We always hear about fuel starvation accidents but we never really hear the pilot's side of the story.
 
Differently....let's see.

NOW before a flight I will do many things different.

THEN...after being in the situation, I would have preferred to be at a higher altitude so that I had more options as far as open fields I could not reach.

A minor mistake I made during this was to put in full flaps right away....this slow me down but didn't allow me to glde a far as I could have. (It might have been a blessing....the field I was aiming for had rows of blueberry trees/bushes running perpendicular to my path...could have resulted in a flip or worse)

If I had it to do over again...I would not have announced "I ran out of gas" on the radio. But I guess that is not something I could have hid forever. Honesty is the best policy but I so wanted to go back to the plane and add a few gallons of fuel and blame it on a mechanical failure...
 
As others have said, thanks for posting this and obviously you did a great job of handling the emergency because you're here to tell the story.

I'm curious if you ever figured out why you burned through the fuel so fast? I would assume you'd have 4 hours of fuel if you took off with full tanks. Since I'm still stuck flying 172's, and flight plan for a 9.5gph fuel burn, I always plan on being on the ground in 3 hours. But I thought that left me a 1hr reserve. I usually check the fuel level before and after each flight and I average about 8gph per the hobbs. So this discussion is both very enlightening to me and just may have saved my skin.

If you don't mind, can I ask a couple of questions?
1) did you lean the mixture at all? Since you said you were flying at 2,500 I'm guessing the answer to that question is no.
2) We're you flying at full throttle, or did you pull the RPM's back a little bit?
3) Have you calculated the fuel burn for the 5 climbs you made? (I think that's the right number, you said 3 landings and a touch and go)

I'm guessing that running WOT, without leaning during cruise as well as climb really sucked through the fuel.

Thanks again for posting this, you have made me rethink my assumptions on how long that fuel in the tank will last and I'm going to double down on my commitment to always check the quantity of fuel in the tanks with the stick before I take off.
 
Differently....let's see.

I so wanted to go back to the plane and add a few gallons of fuel and blame it on a mechanical failure...

Glad you made it through, glad you shared your story.
I am sure you are not the only pilot who has made it through a deal like this and wanted to sneak back with a jug of gas. :p
Planes can be fixed, stuff happens.

I often watch at flyins as pilots all climb back in and head for the hills. You usually see the quick walk around, chalks out etc but very seldom do you see a visual tank check/redip. I guess if they were full when we left x this am, and we only flew here...they still have enough to get home.

Kind of makes sense...easy to be complacent...but we all learned in ppl training to ALWAYS dip/visually check fuel level prior to EVERY flight. Hopefully your kahunas to post this will get at least one pilot to take the extra 30 seconds to check next time.

Excellent helpful post. Blue skies.
 
Thanks Tony for sharing. I played your audio several times. In four minutes after your last air communication you were calling ATC on the phone that everyone is OK.
 
Hopefully your kahunas to post this will get at least one pilot to take the extra 30 seconds to check next time.

Yeah, it's 30 seconds on our low wings but a high wing Cessna takes a bit longer and requires pulling out a ladder so I can see how that would get old.

Also, I think the word you were looking for is "cojones". :)
 
FUEL EXHAUSTION

Most 172's have a plastic(not fiberglas) fairing at the outboard end of the strut. The single fuel vent is located immediately behind the left fairing. If the fairing has a crack in the leading edge, fuel will siphon out the vent in turbulence. It is not something one would notice if you are not looking directly at the vent. I had this happen to me many years ago enroute to Oshkosh. I made a stop short of my planned destination and the tanks were nearly dry. I taped over the crack and on the next leg fuel consumption was back to normal. For multi leg flights in a Cessna(without fueling) the best deal is a plastic tube dipstick. I think Sportys sells these or you can make your own. They do not work on all aircraft. The Cherokees for example have too much diehedral for a dipstick to work.
 
Cojones

Cojones: "a vulgar Spanish word for testicles, denoting courage". I always thought it was Italian.
 
Saturday night a Cessna 421 ran out of fuel comming to Tulsa from Detroit almost made TUL 3 dead 9 kids without dads .Sunday about 8pm a Cessna 177 spun in 200 feet from my home 3 dead POSSIBLE fuel problem NTSB left about an hour ago.
 
It's the 'assumption'...

...that there was enough fuel. An old-timer once advised me.."Assume nothing".

We have a converted 172 with an 0-360 and CS prop on our field that we cannot get to burn under 12 GPH! I've personally flown it and it's a head scratcher for sure. I couldn't get my 0-360 in the RV-6A to burn much over 9.8 running near WOT in cruise.

Both airplanes were leaned until a slight power loss was noted, then richened up a skosh.

Best,
 
Thanks for posting. There is a lot of good info in that story.

jtrusso said:
I'm curious if you ever figured out why you burned through the fuel so fast? I would assume you'd have 4 hours of fuel if you took off with full tanks. Since I'm still stuck flying 172's, and flight plan for a 9.5gph fuel burn, ...

9.6 GPH is 75% power for an O-320 but with all the take offs he did, his real GPH number was probably a LOT higher.
 
it sounds like you didn't account for fuel burn during taxi/takeoff, usually 2gallons is good guesstimate for 172 on the safe side
 
WOW. Thanks for the post. It makes me feel better about my overly cautious approach to fuel levels.

In my RV, I always land with at least 5 gallons (per side) showing on the gauges (which are calibrated to show 5 when I really have 6) even if my totalizer shows that I have more.

When I was flying rental planes, I always checked visually and used a dip stick. I would never take off with less then 1/2 tanks but most of the time, I would fill-up before departing.
 
9.6 GPH is 75% power for an O-320 but with all the take offs he did, his real GPH number was probably a LOT higher.

Would the GPH number really be higher during takeoffs than 9.6? My reason for asking this question is this, according to the POH (C172, O-230-E2D) at 2,500 feet and 2,700 RPM's the fuel burn is 9.6GPH. Would the fuel burn during takeoff be any higher than this? If so, how? Other than increasing the RPMs, which you can't do, how can you increase your fuel burn? I understand that the POH number accounts for leaning, standard conditions, perfect engine, etc, but could that really be more than 1 or 1.5 GPH? It doesn't seem to me that should make the difference between a 9.5 and 14 GPH fuel burn. If I'm missing something here please fill me in. (And I mean that honestly, not being sarcastic. As I said before this is making me question my flight planning so I'm really trying to learn here.)

During takeoff from my sea level airport (Santa Monica) I usually only get 2600 RPMs, but I have a cruise prop on my plane.
 
Differently....let's see.

NOW before a flight I will do many things different.

THEN...after being in the situation, I would have preferred to be at a higher altitude so that I had more options as far as open fields I could not reach.

A minor mistake I made during this was to put in full flaps right away....this slow me down but didn't allow me to glde a far as I could have. (It might have been a blessing....the field I was aiming for had rows of blueberry trees/bushes running perpendicular to my path...could have resulted in a flip or worse)

If I had it to do over again...I would not have announced "I ran out of gas" on the radio. But I guess that is not something I could have hid forever. Honesty is the best policy but I so wanted to go back to the plane and add a few gallons of fuel and blame it on a mechanical failure...

I appreciate your candidness and honesty. I can only hope I act as cool under pressure as you did.

Well done!
 
I will try to answer a few questions.

The engine was a 180hp conversion....not sure on the exact model. I did not lean the engine because most of the day I was at 1500' agl. I did not worry about fuel conservation because with this rental...I don't pay for the gas myself. (another link in the chain that could have been broken)

I did not take into account for taxi or numerous climb outs. Bottom line is...I MISCALCULATED the fuel burn. Although I would love to preserve the "Shadow of a doubt", it is quite clear to me that I just jacked it up, plain and simple.

I know a lot of you guys will take this to heart and try to prevent this. I am glad to see that. I am also glad to see improvements to aircraft which will help prevent this. Many aircraft, especially RVs have a fuel selector valve, not just a valve that says "both". When one tank ran dry it probably would have helped me REALIZE I was burning a lot of gas. Also many aircraft now incorporate some sort of fuel flow guage....this also would help a great deal. A good pre-flight would alert you to potential leaks. While non of these things are fool proof it would substantially lower any risk.
 
Thanks for sharing this, I learned to fly in South Jersey, the expanse of the pine barrens near AC doesn't leave many good places to let down except highways and some small open areas, which may have had the trees cut out and very rough. Had to chuckle when the controller asked you if you could make the AC expressway...I don't like driving on that road let alone try to land on it! I have to say I love the totalizer on my AFS 3500 but I still calc out the fuel burn vs. the distance, at least I have a good fuel burn number to deal with, I always flight planned my days in a 172 at 15 gph...that's what I was taught and never really flew legs far enough in one to see if it was excessive.
 
Gauges?

<The fuel guages were not accurate and as such I did not use them.>

Rental aircraft? Begs the question how long were they known to be inaccurate and why was this 172 left on the flightline with a safety issue like that?

The FBO should be thanking his lucky stars that you and pax were unhurt.. Wonder what his insurance co. has to say about paying a claim on a wreck with a known safety issue that at least contributed to the problem, IMO... Would this accident have happened if the gauges were known to be reliable?

YMMV
 
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<The fuel guages were not accurate and as such I did not use them.>

Rental aircraft? Begs the question how long were they known to be inaccurate and why was this 172 left on the flightline with a safety issue like that?

The FBO should be thanking his lucky stars that you and pax were unhurt.. Wonder what his insurance co. has to say about paying a claim on a wreck with a known safety issue. Would this accident have happened if the gauges were known to be reliable?

Personally, I've never known too many aircraft with accurate fuel gauges.
Do they even really exist? :D ..........considering diheadral, bladders, and such. I've even heard that capacitance systems might not be all that accurate. I wouldn't be depending on my RV's fuel gauges either. I sure like the fuel totalizer.....though. That's one unit, I've been able to trust.

L.Adamson --- RV6A
 
I've always heard that you can't trust the fuel gauges, but except for one AC, I've never had a problem. When they've been incorrect, it's always been on the safe side and that's not something I mind. I'm on the ground before my gauges or watch, whichever is least, show less than an hour fuel.

At fuel rich, without a fuel flow meter you won't know how much fuel you're burning because the power chart show fuel consumption when leaned.
 
Many aircraft, especially RVs have a fuel selector valve, not just a valve that says "both".

C172's have left/right positions on the fuel valve too, and it might be a good idea to use them.

A friend of mine had an off airport landing caused by fuel exhaustion in his C182. The line boy where he last refueled had left a gas cap loose. (He will never let anyone else fuel his plane ever again.) Fuel siphoned out in flight. Fuel selector valve on both, as usual, meant fuel siphoned out of both tanks. No sign that anything was wrong until the engine quit; the low pressure kept the fuel sender floats high, and you can't see the top of a Cessna wing from the cockpit.

I believe Cessna added the 'both' position early on as a safety feature to avoid unporting the selected tank in a slip, but it has its own safety shortcomings.

--Paul
 
It is my understanding that fuel gauges only have to say ZERO when they are empty...that is the only requirement.
 
My first flight instructor was great. I remember one day he asked me "have you ever run your car out of gas?" I admitted that I had. He replied, "then one day you'll run your airplane out". That has haunted me ever since.

Thanks for sharing your story. A good friend of mine was on a primary dual flight with his instructor and they ran out of gas. The instructor panicked and ended up hyperventilating and lost it big time. My friend had to land the plane. Fortunately they made it to an airport. One day I was riding in his VW beetle and doing about 70 mph, he said, "you wanna know what it was like dead stick", he shut off the engine of the bug and we coasted with a surreal sound of the wind rushing over the car. Frightening!
 
My first flight instructor was great. I remember one day he asked me "have you ever run your car out of gas?" I admitted that I had. He replied, "then one day you'll run your airplane out". That has haunted me ever since.

I only ran the car out of gas, because I was broke, and gas was around $0.23 a gallon (late 60's). It was at an intersection with a gas station on three corners.

As to the airplane, the terrain is very rough in many areas I fly. Fuel is always on the top of my mind, and seldom gets below 12 gallons. Lot's of sad stories of people running out........around here.

L.Adamson --- RV6A
 
Thanks

Very sobering story.

I just installed a fuel flow transducer. I have a 0-320 150hp and I was amazed to find that I burn 12.5gph on take off. Also I was amazed to find that that leaning could cut your fuel flow so much. 10.5gph can be leaned to something around 8.5gph without much noticeable impact on RPM?s or air speed.

But a fuel flow transducer won?t calculate fuel flowing out of your fuel caps or other leaks. I will have to admit I have gotten a little lazy with the visual checks, but because of this story, I will always visually check.

Thanks for sharing.
 
If you look at the NTSB site you will find that this sort of thing happens a LOT...WAY more than it should. I can't figure out why the governing authority doesn't require more accuracy with regards to fuel gauges. I have heard it was a financial issue...however, they want us to change ELTs and use a different type of fuel....ironic isn't it?
 
Would the GPH number really be higher during takeoffs than 9.6? My reason for asking this question is this, according to the POH (C172, O-230-E2D) at 2,500 feet and 2,700 RPM's the fuel burn is 9.6GPH. Would the fuel burn during takeoff be any higher than this? If so, how? Other than increasing the RPMs, which you can't do, how can you increase your fuel burn? I understand that the POH number accounts for leaning, standard conditions, perfect engine, etc, but could that really be more than 1 or 1.5 GPH? It doesn't seem to me that should make the difference between a 9.5 and 14 GPH fuel burn. If I'm missing something here please fill me in. (And I mean that honestly, not being sarcastic. As I said before this is making me question my flight planning so I'm really trying to learn here.)

During takeoff from my sea level airport (Santa Monica) I usually only get 2600 RPMs, but I have a cruise prop on my plane.

The POH gives you the amount of gallons to figure for taxi/takeoff for normal operation, add 20% to this to remove variation and you'll have a pretty accurate number regardless of density altitude
 
Good post, glad it turned out like it did. To hear you say, "I'm dead stick and I'm going down" gave me a lump in my throat sitting on my couch. Nice work, not letting that panic set in, that has to be more than half the battle for a safe outcome in a situation like this. No one truly knows how they will handle that until it happens to you.
 
Numbers per the POH

The POH gives you the amount of gallons to figure for taxi/takeoff for normal operation, add 20% to this to remove variation and you'll have a pretty accurate number regardless of density altitude

POH says 2.6 gallons for taxi/takeoff/climb to 5,000feet at standard temps and max weight, so we'll half that to 1.3 to 2,500.

So assuming 5 takeoff's and climbs to 2,500 that's 6.5 gallons.

Cruising WOT at 2,500 is 9.6GPH per the POH (assumes leaning)

3 hours @ 9.6GPH = 28.8 gallons

28.8 + 13 = 35.3 gallons burned per the POH (I'm double dipping a bit because I'm not subtracting the time spent climbing from the time cruising, which would take this number down by 1 gallon per climb, or 5 gallons total)

Assuming standard tanks you've got 38 gallons on board.

There it is. Wow, I never would have guessed it if you asked me, but when you run the numbers per the POH it makes sense.

Thanks again for sharing you're story. I have learned a couple of couple very important things and will modify my flight planning accordingly.

1) Always double check the fuel burned to climb to altitude per the POH and add that in. Don't assume it's covered with a blanked 9.5GPH burn.

2) Always, always, ALWAYS physically check the amount of fuel in the tank with the dip stick prior to takeoff.
 
in response to the above which is a bit large to quote- yep! so add 20% per my own rule and you'll still have a bit of a pad....
 
I can't really remember back that far...but for whatever reason I remember that the usuable fuel onboard at 43 gallons. I think I used that and then some....

I think the POH is a general rule of thumb but I would not rely on it to save my behind. On any new airplane I flew I would fly it in my normal manner (taxi, runup, takeoff, climb to standard cruise) for one hour. Then land and fill the tanks and see how much fuel I actually burned. I once got advice that said "Fly just ONE airplane until you get to 500 hours. Don't switch planes." While I see the wisdom in that, it is not always practical. But there is something to be said about owning a plane and learning THAT plane.
 
But were the tanks really full to start with?

One thing I've learned over the years is that tanks may not be 100.00% completely full when they look full on casual inspection, right after fueling. If your tanks are down 3 or 4 gallons when you start, and you're counting on 5 - 6 gallons of reserve... My RV-4 would do this to me, and I'd rock the wings to get the air bubbles past the ribs and get that last little bit of gas in.

Thanks again for your posting! This kind of raw honesty is what will help us all stay in the air and out of the repair shop (for airplane / people).

Ed
 
thanks for the post.

1st - the FAR's state that fuel gauges are only required to be accurate on empty.

2nd - It's my understanding that we typically use RPM's to determine fuel burn. But this is not quite accurate even though most of the time we can figure we will get X speed at Y RPM at Z altitude and burn x.x GPH based on the RPM.

In reality the fuel burn is directly related to the throttle position. If we are WOT at level cruise, low altitude, the RPM's will be at/near redline and fuel flow will be high.
At that same WOT and pitched up 30 degrees, we will be climbing, and the RPM's will be significantly lower, yet the fuel burn will be just as high.

Likewise, I can shut the engine off and dive, keeping the RPM at redline yet not burn any fuel.


Briefly looking at a C-152 POH. The fuel burn for cruise at 2000' and 2400 RPM is 6.1 GPH but burns 8 gph on the climb to 2000'.


(as always, my 2 cents; correct me if I'm wrong)
 
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...that there was enough fuel. An old-timer once advised me.."Assume nothing".

We have a converted 172 with an 0-360 and CS prop on our field that we cannot get to burn under 12 GPH! I've personally flown it and it's a head scratcher for sure. I couldn't get my 0-360 in the RV-6A to burn much over 9.8 running near WOT in cruise.

Both airplanes were leaned until a slight power loss was noted, then richened up a skosh.

Best,

I just finished putting 19 hours on a 2001 model 172R with IO360 and GAMI-jectors, FP prop, takeoff power was 11-13gph depending on density altitude and 2500 rpm cruise at 6500 LOP was 7.5-7.8gph. Flew it from southern Maine to west Texas over 3 days, lots of time to check the numbers.
 
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I just finished putting 19 hours on a 2001 model 172R with IO360 and GAMI-jectors, FP prop, takeoff power was 11-13gph depending on density altitude and 2500 rpm cruise at 6500 LOP was 7.5-7.8gph. Flew it from southern Maine to west Texas over 3 days, lots of time to check the numbers.

I'm curious as to the notation of takeoff power? Generally you don't use GPH for this, you use a fixed amount- same for climbing, you use a fixed number for each altitude based on the climb performance charts. Static numbers are the way to go here, dynamic flow values are too difficult to calculate given the minutes spent doing a runup and takeoff. Not saying your numbers are wrong, just adding to what you came to post- good info!
 
I'm curious as to the notation of takeoff power? Generally you don't use GPH for this, you use a fixed amount- same for climbing, you use a fixed number for each altitude based on the climb performance charts. Static numbers are the way to go here, dynamic flow values are too difficult to calculate given the minutes spent doing a runup and takeoff. Not saying your numbers are wrong, just adding to what you came to post- good info!

Full power and full rich is always used for takeoff (low-altitude airports, obviously) - I'm only talking about the resulting fuel flow.

To be honest, I only glanced at the fuel flow indicator briefly on a couple takeoffs, that is my memory of where it was. I was busy keeping the airplane where it was supposed to be and didn't spend much time being precise on the gauge. I do remember thinking that that seemed 1 or 2 gph low, but over the rest of the trip the fuel flow indicator matched up quite nicely to the number of gallons pumped. Initial climbouts were consistently 11-13 depending on airport elevation and temperature. The '01 model 172R has 53 gallons capacity, we were looking for a bathroom or restaurant on every leg before fuel was an issue.

I have always made the habit of topping off the tanks on EVERY full-stop shutdown where I get out of the airplane - most lineboys can top it off as fast as I can run to the john, there's just no excuse not to do it. You can't burn fuel you don't have.
 
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Belt+Suspenders

I use the Belt & Suspenders method...

#1, my plain old Van's gauges which are mounted directly at eye level, hard to miss...

#2, a superbly accurate fuel flow transducer keeping me constantly apprised of fuel remaining.

#3 visual tank check before each flight. Even 1/2 hr flights.

#4 I have flown level letting one tank get down to bouncing at empty, switched tanks, landed, filled tank a, noted I had 2 qts. left, repeated with tank B. So think when they say "empty" they are accurate at least for now.
Some do this but let it run out.

#5 Plan to land after about 3 hrs or when tanks/transducer say one hour left.

Confession:side note: Before I built my -6a, partner and I shared one that had fuel gauges mounted low by the fuel valve. Went thru checklist apparently skipping the part "Switch to fullest tank" before landing at St Maries, ID between two mountains. I was lucky that day because I put over 18 gals into a 19 gal tank. That is why on my build the gauges are staring right at me...
 
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Good Timing

This thread contains very appropriate material for those planning to make the annual pilgramage to Oshkosh next week. On one of my trips I was surprised at how little fuel I had remaining in my tanks when I landed at a planned stop about an hour away from OSH.
Y'all be careful out there!
 
The NTSB and McNall reports have far too many of these events. I have run out of gas in a car. Several times. Most recently last year I think and I coasted into a gas station. But I will NOT run out of fuel in my plane.

With an engine monitor, unreliable fuel gauges, beaucoup hours in one plane and a conservative approach to fuel reserves, I am dead set on never running out of fuel flying.

On a trip back from the Caymans I had to fly in less than Colorado weather in Florida. My VFR fuel reserve went from one hour to two. That required at least one other fuel stop. That takes time but it gives options.

Several years ago I went to a KR fly-in back east. After landing and getting refreshed, I was going to make a stop at three or four other states with less than full fuel. It was very soon after take-off when I found that fuel flow was significantly higher than I was used to at altitude (duh), that I had to change my plans. I should have refueled. It was not a safety issue but did force a change in that side trip. Had I filled the tanks I could have completed the trip as planned.

I have run tanks dry to determine usable fuel. Good exercise but not when your fuel selector is set at BOTH. While I could conceivably run a tank dry on longer cross country flights, I have decided that I want to keep five gallons or so minimum in a tank just in case. In case a fuel cap comes off the other side...or that tank is plugged. Whatever.

On my last trip to KELK, OK, once I got to 11,500', the fuel remaining duration plus time to climb came to five hours. Three hour legs are long enough and provides at least one hour reserve.

All this to ensure that I never find out if I am as good under the duress you experienced. Great job once you had a problem.

Please consider publishing this in a "Never Again" type forum. I keep hoping that we can end some of these preventable events that kill too many. That may never happen but your account may help.

PS, the vehicle that I let run out of gas is a 1988 Chevy S-10 Blazer. If that happens to you, and soon the engine does not seem to run right, consider replacing the fuel filter. Apparently being a bonehead and running out of gas in a SUV must put trash in the filter. I just realized that I need to be as diligent in my car gas management as I am with the RV.
 
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