We are talking about that vital lifeblood that keeps our airplanes in the air... FUEL!
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00:01
Behind the Prop Intro
Clear prop S73 Cherokee number two following twin traffic three mile final one trolley.
Bravo makesford in Runway two five going four mile.
00:10
Nick Alan
This is behind the prop with United Flight Systems owner and licensed pilot Bobby Doss and his co host, major airline captain and designated pilot examiner Wally Mulhern. Now let's go behind the prop.
00:23
Bobby Doss
What's up Wally?
00:25
Wally Mulhern
Hey Bobby, how are you?
00:27
Bobby Doss
I am fantastic as always. This week has been a big week. We just had our big open house yesterday. Lots of people came and this show will be released tomorrow on Monday. I talked to many people, had many people ask a bunch of different questions and we couldn't record everything that somebody, everybody brought up. But we're gonna record a show today on some timely stuff that's kind of happened. We've heard about it and Wally's experienced some of it on checkrides. And it's all about fueling and fuel. We talk about fuel a lot because it is extremely important in general aviation or all aviation. And we're gonna talk about a bunch of different stuff today. Quick overview of the outline that we're gonna talk about. We're gonna go through really how to fuel yourself, do it yourself, fueling.
01:19
Bobby Doss
We're gonna talk about something and what we're looking for and what we need to check for. And we're gonna go back to some basics on taxing and ground operations to save you some time and fuel. Top three techniques to maybe save you some time or mostly fuel in the air. Computing fuel and distance and time. If you're taking a check ride or doing a flight with the family. Some leaning techniques in the air. Briefly talk about lean of peak in fuel injected aircraft and then wrap up with a conversation about personal minimums. So Wally, you say it all the time. Can you repeat what the top five most important things are in flying?
02:02
Wally Mulhern
Yeah, I like to say there's five distinct different things and number one is fuel, number two is fuel, number three is fuel, number four is fuel. And everybody, what is number five? You guessed it.
02:23
Bobby Doss
Fuel.
02:25
Wally Mulhern
Fuel is the one thing that we cannot flip fly without. Okay, we can fly without electricity, we can fly without an engine for a little while. But if we don't have fuel, that airplane is not going to fly. You know, we're going down. So it's pretty important. Very important.
02:54
Bobby Doss
I'm sure I've said this on the show many times, but my first time to ever fuel was all by myself in a remot location and it was without an instructor. I didn't have the luxury of getting an instructor to show me, and I preach it a lot with the team today that they should be teaching people how to fuel aircraft. They need to know how to use the systems at a remote airport. It's such a slippery slope that we don't know how to do it, that we might not do it because we don't know how to do it. We don't want to be embarrassed and it's not that difficult. If, if you own a gasoline vehicle, you've gotten gas at the pump many times and it's really similar.
03:39
Bobby Doss
It's just the configuration of a plane next to some fuel pumps is probably a little different. But let's talk through the key elements of getting fuel. At my flight school, it's, we got fuel service, but I think we should try to do self service during your training. The biggest first step to fueling, to getting fuel at a remote airport or somewhere with fuel pumps, is to make sure that you approach the fueling area safely. Right. And you watch the wingtips. There's probably stuff everywhere. And if you've ever watched someone fuel a plane, they have this magical little clip that they always clip onto something.
04:21
Bobby Doss
That clip is connected to a wire and that's really a grounding wire to make sure that there's not an inadvertent spark or something happen when they put the nozzle of the fuel into the plane or vice versa from static electricity. We don't want any sparking happening. And then there's this big nozzle. And I think people that maybe have never fueled a plane before, you can't let that thing rest in a fuel tank of an aircraft. Right, right. I don't know when the last time you fueled a high wing was, Wally, but you know, you got a 30, 40 foot hose that's got a lot of weight full of fuel. You got this probably 5 to 7 pound fuel nozzle and you don't want it to crank and bend the inlet of that fuel. Maybe the cap can't get back on.
05:16
Bobby Doss
Maybe you create a small crack that creates a small fuel leak. You've got to be really careful and probably no question need a ladder to be able to see in that fuel tank so you don't spill a bunch of fuel out over the wing when you finish your fueling. And then I think it is remembering to replace the fuel caps, you're probably not going to have the nozzle, the hose, the fuel cap all in your hand and be able to magically pull the nozzle out, put the fuel cap back on. There has to be a real effort to make sure you get those fuel caps back on and make sure they're snug and tight and then put the hose back up.
06:00
Bobby Doss
Most, I would think most airports would have a, an electronic reel that would reel in the hose, but if not, you're going to have to hand crank it and get that hose back on the reel and then pay for the fuel. Probably add an electronic push pin pad, some sort that takes credit cards and then remove the ground clip and make sure you check both fuel caps for sure. What's the next last thing that you should do if you ever put fuel in a plane, Wally?
06:32
Wally Mulhern
Yeah. Well, well before we want to get into that, I want to just echo what you said, Bobby. I mean I, my first job in aviation was as alignment fueling airplanes. So when I got into. Back into general aviation, it. I didn't even think that this was something that I needed to teach to my daughters. But then all of a sudden I realized, well, geez, they've never done this before. So yeah, it is something I have to, it was just kind of something that I assumed. And you know what happens when you assum. To all the CFIs. Yes, this is something that needs to be taught to your students. So please do this.
07:16
Wally Mulhern
I have heard horror stories of students stopping somewhere on a cross country and they needed fuel and their only option was self serve fuel and they didn't know how to do it so they just bypassed getting fuel and came home. And the cases, I've heard of this multiple times, they've always made it home, but they came home with a whole lot less fuel in the tanks than they should have. So this is absolutely critical. Really.
07:51
Bobby Doss
And well, I know a couple tragedies too where the fuel didn't get done. One story I heard, and there's an NTSB report about it, that the pilot was offered a fuel full fueling fee and said no. And because of that fueling fee didn't have enough fuel to come home for fuel full service. Right. We just got to get the fuel. You got to have the fuel to be able to make your destination and then have your reserves.
08:17
Wally Mulhern
Yeah, yeah. And, and fueling a high wing airplane can be a cumbersome operation if you have two people. It, it really makes. Makes life easier. Somebody can get up on the ladder, someone can hand them the, the fuel hose are and vice versa they can hand it back down to you and, but you know, solo, cross country, you're solo, so you might be doing this by yourself. So this is so critical to the CFIs and you gotta, as you talked about the fuel fee, you gotta make sure you got a credit card to pay for it and, or a debit card or whatever. Because a lot of these small airports, you know, you can't go in and pay cash or write a check or whatever. You know, all it is a self serve machine just like most of use to fill our cars up.
09:16
Wally Mulhern
One thing I will say about doing this is to be courteous. Just like, you know, if I go to the local convenience store, I put gas in my car and then I decide to go in and go get a Coke and something to eat, you know, I look around and if there's lines of cars waiting to get up there to get filled up, I move my car to a different parking spot. Most of these smaller airports, there's only room for one airplane at the fuel pump.
09:49
Wally Mulhern
So if you fuel and then you're gonna go and use the restroom and rest for a while, file a flight plan, call the weather briefer, look around and if you got other airplanes coming in and it's a busy airport, get the airplane out of the way of the fueling the fuel pump and then go do your resting or whatever you need to do. But back to your original.
10:14
Bobby Doss
That one time that I, the one time that I did get fuel, I didn't understand why this helicopter was hovering. It was literally three feet off the ground watching me get fuel. And I, it was a really small airport and so he was over the grass and I was like, what is this guy doing? It was making me feel pressure. And I finished and this lady walked out of like a mobile home and she goes, he wants you to move is what he's waiting to get gas too. So it might not just be an airplane that's waiting. I found it very awkward that guy was sitting there with that helic. So be courteous, as Wally said. For sure.
10:52
Wally Mulhern
Yeah, yeah. So your original question is what now? Okay, so we filled the airplane up, we've put the hose away, we've unhooked the ground, we've got our credit card receipt, we're looking at the amount, the fuel costs and our blood pressure goes up and it's finally settled down. So now we've put a bunch of fuel in our airplane. Now we want to make sure that we've really Put fuel in the airplane. So what am I saying is we're going to. We're going to make sure we didn't just fill our airplane up with water. And you know, in a nutshell, that's what we're doing by something the airplane, making sure the fuel is. Is pretty good.
11:31
Wally Mulhern
What I like to do is if I am, you know, in the scenario I gave where we're going to fill the airplane now, we're going to go into the. The FBO or whatever it is, we're going to use the restroom, we're going to grab a drink, we're gonna file our flight plan. We're gonna call the weather briefer. I like to fuel the airplane, then go do all that and then come back and sump the tanks, give it. Give the fuel. And I don't know how long. I don't know. I mean, somebody could probably tell me it takes 20 seconds. I don't know how long it takes if there's water in the fuel for all that to settle in the bottom of the tanks. I would suspect that it's pretty quick, but we definitely need to sump the tanks.
12:18
Bobby Doss
Yep. And it's not just the water. We're looking for some impurities. Right.
12:21
Wally Mulhern
They could add.
12:23
Bobby Doss
Somebody could have done some heinous to that fuel pump. Right. Someone could have taken the cap off the in ground tank and dump some sugar or sand or whatever. You don't want any part of that for sure. And so you're. You're not trusting anybody. You're not trusting it because it's an airport with a fuel tank.
12:41
Wally Mulhern
You.
12:42
Bobby Doss
You're going to challenge it in every sump and make sure there's nothing in there that's going to cause you any issues.
12:51
Wally Mulhern
I will tell a story about flying with my father. This would have been back in the 1960s in a Beechcraft Queen Air. We went somewhere from White Plains, New York to somewhere in upstate New York. I want to say it was Poughkeepsie, New York, but I don't really remember. But I remember this vividly. I remember the guy coming out and fueling the airplane. And after he fueled it, my father went over and he sumped the tanks. And the guy, he was an elderly gentleman. He. He looked at me and he said, you know why your father's doing that? And I looked at him and I said, no. And he said, because he doesn't trust me. And for. For a brief time, it was very awkward. You know, he's telling me that my father doesn't trust him.
13:53
Wally Mulhern
And then he looked at me and he said, and he shouldn't trust me. That came from the fueler, he said, and he shouldn't trust me. And then I kind of went, oh, okay, everything's okay. I was probably a 7 year old at the time when this happened, so this was a long time ago. This long time ago. But yeah.
14:14
Bobby Doss
And I tell people all the time in our orientations and onboarding students, my instructors are going to check the fuel and the oil no matter what, every time they get in an aircraft. It's, it's part of our SOPs. And the fact of the matter is I tell them you shouldn't trust the instructor and the instructor shouldn't trust you. And it's not a indictment, it's just a fact of life. We make mistakes and you just never take any chances with fuel. And that's kind of theme of today, for sure.
14:43
Wally Mulhern
Yeah, absolutely.
14:45
Bobby Doss
So once we've sunked it, we know we're good. I think there's some tips and tricks for on the ground and I, I think I've thought this, I think Wally and I have both thought this, but we've never seen a written down. And I read an article on the AOPA website which I thought was interesting and it was really about don't leave fuel on the ground. And the thought process is, you know, if you can, if you have room, put the fuel in your tanks. But it's also a byline of that article that says don't burn a lot of extra fuel on the ground. So you want to try to be expeditious in your ground operations for more than one reason than just the fuel.
15:25
Bobby Doss
But you definitely don't want to sit on the ground and think you're using the POH amount, whatever that POH amount is for taxi takeoff and landing, and spend an extra 30 minutes running the aircraft and burning another three or four gallons of fuel. So I guess the tip would be expeditious. Wally, how many extra minutes do you think you spend in the cockpit with the engine running that maybe you shouldn't.
15:53
Wally Mulhern
If on your check rides, on the, on check rides. There's a lot, you know, and I think a lot of it may be nerves. And so the applicant wants to do that checklist maybe 17 times with me there rather than one time. I'm being a little facetious with that, but you know, have your plan. And you know something, all the aircraft POH's have a set amount of fuel for taxi, but it's a function of time. You know, how can you say, well, we're going to be burn 1.4 gallons for taxi? Well, if you're located right at the departure, under the Runway, an uncontrolled airport and the engines warm, you know, maybe you burn a half gallon, but you're at a busy airport with lots of traffic and it takes you 45 minutes to get off the ground.
16:56
Wally Mulhern
Maybe, I don't know, maybe you're burning more, I don't know. So that number of 1.4 gallon or whatever the POH says, it's a guess, it's an educated guess by the manufacturer and it's probably pretty close, but just keep that in mind.
17:17
Bobby Doss
Yep, no doubt. So save that fuel on the ground and then there's ways we can save fuel in the air. I can remember as a student really never being taught much about the rev knob. That'd be the mixture control in most these single engine aircraft. And I think leaning really anywhere where it makes sense makes a lot of sense. I think leaning on the ground when you are taxing is a huge advantage to saving fuel and prevents some carbon buildup and maybe other issues in that engine. But leaning in the air, most POH's say at 3,000ft, lean as needed or as appropriate. And that is probably sea level in Houston most days. Wally, would you agree?
18:04
Wally Mulhern
Yeah, absolutely.
18:07
Bobby Doss
So It's a, it's 95 degrees in Houston, hot humid day. I would bet pressure altitude is probably somewhere between 25 and 3,000. It's not going to take much elevation or altitude to get to a point where it's going to make sense to lean the engine as well and save some of that fuel. Right. Maybe not when you're practicing maneuvers, ground reference maneuvers at 2500 or 3000ft. But again, pressure altitude. But the thought process is if I'm trying to get to Austin and I've got my family of four in that aircraft, I would like to land with absolutely as much fuel as I possibly can by design, not by accident. Right. So I want to lean that aircraft. I think the second tip of in the air that I didn't learn till my commercial days was really economy cruise. Right, Right.
18:59
Bobby Doss
In most cases, economy cruise with a good lean setting will probably save you about a third of your fuel burn and you probably lose, let's call it 5 knots of airspeed for 20% of fuel value. Right. And hour to Austin. For me, that could be a Couple of gallons. I would rather have those gallons both for money reasons. Right. To save that 12 bucks in today's fuel prices or to just make sure I have some, if they make me go around or there's something on the ground that prevents me from landing there and I got to go a little further or go back somewhere and come up a little shorter. So. And then I will say I had a good instructor for my multi engine training and he taught me to send like a commercial pilot.
19:49
Bobby Doss
And a lot of it has to do with use no, no fuel and probably expend all that energy you have from climbing all that way up there. So if I'm at 5,500ft, there shouldn't be no power in there and I should be descending at a rate that uses all the energy that I've already put into the aircraft by climbing that high. So cruise descent should be calculated. You should know what you want to do and it should be really all the energy you have in the aircraft without a lot of power. Meaning not spending a lot of fuel on the way down as well.
20:27
Wally Mulhern
Yeah, I think, yeah. I would, I would venture to say that most of our, my private pilot applicants, their energy management is not the greatest. I remember my father telling me in our Cherokee140 that I had as a private pilot. He's, he said to me, you shouldn't ever touch the flaps unless the power is at idle. You know, he's thinking, well, and you know there's, that's, that's not a, an absolute. But you know, why are we on downwind at 2300rpm and putting a notch of flaps in to help slow us down? Well, why not just pull the power back, leave the flaps up. So you know that's kind of getting into the finer things of energy management and that sort of thing. But you know, the other thing is health of the engine.
21:36
Wally Mulhern
We, we need to give the engine the proper amount of fuel and just to be dumping a whole bunch of fuel in there is not really good for the engine. You know, it's like a highly trained athlete going through, you know, in a training regime they may be eating 5, 6, 7, 8,000 calories a day. And if, you know, if you and I did that, we'd look like the Goodyear blimp really quick.
22:06
Bobby Doss
Yes, yes, no question. I guess I should exercise is what you're saying, but I hear you, I'll work on that.
22:14
Wally Mulhern
Yeah.
22:16
Bobby Doss
So we talked about ways to save fuel, I think you need to know how much fuel you're going to burn. Right. And we've talked about this a few times, but there's a distance measurement that I think that's all I thought about when I was driving cars and became a pilot. I didn't know that. We only talked in the terms of time. But we have to know how far we're going and at what speed we're going to be able to go. So we can calculate the time, and once we have the time, we can then make some really good calculations on how much fuel we're going to burn to travel that ultimate distance. Right?
22:53
Wally Mulhern
Yeah.
22:54
Bobby Doss
And I know there's a lot of rule of thumbs. I know you want rule of thumbs, but also want accuracy as well. What are your thoughts on how we take and calculate the fuel we need to go that time?
23:09
Wally Mulhern
Well, I hear all the time. You know, I'll say, okay, well, how long is it going to take us to go from here to there? And the applicant may say, that's going to take us two hours and 29 minutes. Like, okay, good. That. That sounds reasonable. And I'll say, how much fuel are we going to burn? They'll say, 24.9 gallons or 25 gallons. I'll say, okay, all right, so how much fuel are we going to land with? And, you know, if we're in a Piper Warrior, they'll say, we're going to land with 23 gallons. I said, okay, that. That sounds good. And I said, how did you come up with that fuel burn? That. That rate of fuel burn? And I saw, well, that's just what we use. And I'll say, well, okay, how did we come up with that?
23:59
Wally Mulhern
Well, that's what my CFI said. And then we'll dig into it. We'll get into the book, and. And, you know, the word is out there that the applicants are actually doing a much better job. This was kind of the. The norm maybe six years ago. Now. They're pretty good, though. They'll come back and say, well, the. The actual fuel burn is 8.2 gallons per hour. And here it is in the chart. This is how it works.
24:28
Bobby Doss
Or.
24:28
Wally Mulhern
Or whatever. Whatever the number is. But I'll just. I use 10 gallons per hour. And there's. There's pros and cons of that. That's. That's like saying, well, I think the Happy Meal or the value meal at XYZ hamburger joint is $8.50. So I'm gonna. I'm gonna put $10 in my pocket. That's probably a good idea. But we may get to the point where we're a little bit overweight. Okay, we're 15 pounds overweight. Can we afford to take two gallons of fuel off the airplane to get to where we're now 1.1pound underweight and, you know, we may get down to the. Where we need to have the exact numbers. So we need to be able to figure that out. We need to be able to calculate it.
25:24
Bobby Doss
Yeah, I'm a fan of 10 because it's good mental math. But at the same time, before we started recording, we did some POH looking and you say Warrior, I say Cessna. But In a Cessna 172Pmodel at 6,000ft pressure altitude, the math is really a much smaller number. It's, you know, that cruise performance. We'll call it 2300 RPMs. We're only burning 6.4 gallons of fuel. And that's a much smaller number than 10. If you say 10 and you take away. We say 100, you take away 36. That's more than a third over. Guessing right. I think everyone's gonna claim personal minimums. Well, yeah, I'm doing that for my own personal minimums. To pat it. To pat it. Well, then maybe we can't take the dog. Maybe we can't take a passenger. Maybe we can't take that other bag.
26:20
Bobby Doss
It does make sense to know the performance charts. I think all POH is after 1980. It's section 5 of your POH. You can quickly thumb through those. Do some fuel calculating. There's a climb calculation char on the page before the cruise calculation chart. And you really should just know your numbers. Yeah, it's gonna, yeah, it's gonna make you feel more confident and it's gonna make you a better pilot.
26:46
Wally Mulhern
Yeah, absolutely. I mean, and especially, you know, a commercial pilot applicant. I mean, we ought to be able to zero in on these numbers and be pretty darn close. And I think it's a great idea for you to say, okay, I'm gonna burn X amount of gallons on this flight. When you get to your destination and you fuel it up, see how close you are. Because now that's gonna give you either confidence or non confidence in the airplane's poh. And if it's way off, you should probably start investigating. Why is it going, you know, I was supposed to burn, you know, 24 gallons on this flight, and I burned 32. Something. Something's not right. That's a 33 no question.
27:35
Bobby Doss
And I think yeah, some of the digital stuff maybe gives us too much information at times because we start to recognize a fuel burn is not equal on both sides. It's still a vented fuel system. So maybe a vent problem could be a flow problem, could be a lot of things. But we probably rarely check our non digital aircraft to know really did we burn 5 gallon. If we had the, if we had it on Both in a 172. Did we really burn 5 gallons out of each side when were expecting to burn 10 gallons and if not that's an issue. Maybe we have a gasket on a fuel cap that's loose and we're losing fuel the other direction. That could be really a slippery slope if you go on a long trip and don't do the math just right.
28:23
Bobby Doss
So make sure you do dipstick those tanks and that you maybe even before you fueled them so that you know that you burnt exactly what you were expecting to burn. It's going to make you a much better pilot if you have a fuel.
28:36
Wally Mulhern
Yeah.
28:36
Bobby Doss
And you might go ahead.
28:40
Wally Mulhern
No, as I was going to say, most of us you know, are probably renting airplanes and you go out to the flight line and it's full you and you go out and you fly for an hour and a half. You come back and you don't. We don't really monitor it. So if you are on a cross country this is a really good time to monitor it. And you know, if something seems fishy, write it up, let the flight school know, hey, I just went on a two hour flight and burned you know, excessive fuel and you know, let them investigate that.
29:17
Bobby Doss
No doubt I would want to know that. So please do that for sure. I was gonna say if you're flying a fuel injected aircraft and you have some good systems operating your plane, lean of peak is something you may want to consider. I wouldn't do it if you didn't read the POH or didn't read their manuals on how to use that feature or functionality of that aircraft if you have the right equipment. But running at lean of peak I believe is something Mike Bush would support. What I would call a famous aviation mechanic and others would support running lean of peak as well. Not just for the fuel burn but for the way that it's going to help the engine perform as well.
29:58
Bobby Doss
All ways to save you fuel in the air to hopefully get to your destination with as much fuel in your tanks and as much Money in your wallet as possible. Wally, let's close out with some personal minimum stuff on fuel. I think everyone kind of defaults to the hour rule, right? VFR day is 30 minutes, nights, 45, IFRS, 45. But we all say an hour. Is that something you agree with?
30:32
Wally Mulhern
Yeah, it just depends. Boy, that. That's a tough one. I'll hear a lot of people say 30 minutes more than the minimum. So a lot of people will say hour 15 at night, an hour during the day. We're talking about VFR rules here. All I got to say is, you know, if I'm in an airplane that's, let's say, a Piper Warrior, if I'm fueling it up and I'm putting 40 gallons in the airplane, I'm having a oh, my gosh. Moment. Having said that. Having said that, I fly a triple seven, and landing with an hour and an hour, 15 minutes worth of fuel is. It's pretty standard, you know, hour and a half in that range. So, you know, I do it in a big airplane. Just know that you. You. You just keep your options open. Hey, I'm going back here.
31:39
Wally Mulhern
And, you know, minutes is fuel. Don't. You know, don't think of fuel as gallons. Think of fuel as minutes. How much fuel does my airplane hold? It holds 300 minutes worth of fuel or whatever, 240 minutes. Think of fuel as minutes because now we're flying long, and it's supposed to take us hour to go from here to there. Now it took us an hour and 15. It took us 75 minutes rather than 60 minutes. Well, now we have less fuel in the tank, so just think of fuel as minutes.
32:17
Bobby Doss
Yeah, that's a great tip, because it could be a point in your future where every minute counts and you're. Hopefully we don't. Any of us get to that point, but I guarantee you, if we got to that point, for me, I'd like to have 30 more minutes of fuel instead of three more minutes of fuel. No question.
32:35
Wally Mulhern
There's an old saying, better to be on the ground wishing you were in the air than to be in the air wishing you were on the ground. And I've. I'm on the ground all the time wishing I was in the air, but, I mean, almost daily. But there have been a few times where I've been in the air wishing I was on the ground. And that is a really bad feeling.
32:59
Bobby Doss
So far, I haven't had to feel that way yet, and hopefully I won't. As all of you listen to the show. We hope that you get some tips and tricks out of today's episode. As you put fuel in your plane, make sure it's clean and free of water, and stay behind the prop.
33:19
Nick Alan
Thanks for checking out the behind the Prop podcast. Be sure to click subscribe and check us out online@bravetheprop.com behind the Prop is recorded in Houston, Texas. Creator and host is Bobby Doss. Co host is Wally Mulhern. The show is for entertainment purposes only and is not meant to replace actual flight instruction. Thanks for listening and remember, fly safe.