How Much Fuel Do You Need?

When I got my private pilot license I did what many new pilots do. I took family and friends up for a ride.

On a clear day with calm winds I was preparing to fly a Cessna 152 with a friend of mine who had asked to go up. This was my third or fourth flight with a passenger.

During preflight, I found that the fuel tanks were not full but they appeared to be near the top. I did not use a fuel stick to measure the exact amount but I reasoned that it was enough. This was a big mistake. I considered asking for fuel but I didn’t want to bother the line service guys.

We departed and flew over our houses and to a nearby airport. Finally, we decided to return, although I very easily might have continued flying. Fuel was the farthest thing from my mind.

We landed and put the plane away. But that’s not the end of the story.

A few days later I was called into the Chief Flight Instructor’s office. He informed me that the fuel records showed that I had less than 20 minutes of fuel left when I landed.

Landing with this small reserve can happen on a well planned out flight if the winds change, but it was particularly dangerous in my case because I was not aware of the urgency of the situation!

Never Again

I learned a lot from that experience. I never flew again without knowing exactly how many gallons of fuel I had onboard.

In addition, I set personal minimums in excess of the legal minimums.

If you feel like you are bothering line service with a small fuel request then say something like “Hey, this might only take 2 or 3 gallons but I want to be totally sure.” If the line service technician isn’t a complete sociopath then they will understand and be more than happy to help you.

The Rules

The legal minimum amount of reserve fuel that you can depart with is enough to fly for 30 minutes after you reach your planned destination. If you are flying IFR or at night, then you need 45 minutes of reserve fuel.

I very strongly encourage you to use a safer personal minimum. The fuel gauges in many light aircraft are very bad and give you little idea of your current fuel quantity.

I use a personal minimum of 1 hour for day flying and for night or flight in IMC I want to have a lot more than that, sometimes double the required fuel.

Fuel exhaustion is the most common cause of engine failure. So by following a safe personal minimum and taking no chances with fuel, you can significantly decrease your odds of having to face this emergency.

Consider these questions:

  • Do you have a personal minimum for fuel?
  • Will line service really be “bothered” if you ask for more?
  • Did you verify the fuel level yourself after getting a top off?
  • Did you check that your fuel is clean and of the correct type?


What is Line Service?

At most local FBOs the ground crew is referred to as line service. Sometimes they are called ramp agents or line service technicians. (FBO stands for “fixed base operator” and it just means the company at the airport that provides services to your plane).

The great men and women of line service are all friendly but their interest and involvement in aviation vary. Some of them are pilots or student pilots, and others like planes but aren’t planning on taking lessons. There are even some line service technicians who don’t care about planes at all!

Depending on the airport, a big part of the job for a line service technician is friendliness. These are the people that greet you and your passengers after a flight. They are selling their FBO services to your passengers just as much as they are selling to you.

If you run across an unfriendly or rude line service agent let the company know. Thier negative attitude is not just uncomfortable, it can also be dangerous or costly. Consider someone doing a hasty careless job while towing a multi-million dollar jet. CRUNCH! Or maybe they are fueling your Cessna 172 with jet fuel. Or what if they bump into your wing and don’t tell anyone…..that can get you killed!

I, myself, worked line service for about 6 years across 3 airports including Phoenix Sky Harbor. If you are young and interested in aviation, line service is a great job, and some flight schools will give you a discount if you work there (ask before you apply).

At most small airports line service will operate with a crew of just 1 – 4 employees sharing the various jobs across the field. Each line service agent at a small airport does every job. They drive tugs, fuel trucks, luggage trucks, deice trucks, etc… They know how to handle various types of planes and they learn how to push planes into a hangar in tight formation. They act as wing walkers, standing next to the wing to let the tug driver know it is safe from obstacles. They act as marshallers, waving their orange wands to let pilots know where to park. They operate ground power units, air conditioning units, air start units, lavatory service carts, and all manner of machinery needed to support air operations.

When dealing with line service be friendly like you would anywhere, but understand the relationship. You need to tell them what you need for your plane and they will do it. You need to make your own fuel decisions. Even if you are a newly soloed student pilot and you feel like others know more than you….you are the one calling the shots!



Accident Study: Helicopter in the Water

I have been watching this particular accident for more information since the day I first saw it in the news. In short, a helicopter was giving a routine tour of New York City  when it was forced to make an emergency landing in the Hudson river. The pilot survived but all 5 passengers drowned.

Source: NTSB

What Happened?

Liberty Helicopters gives tours of New York with the doors removed and passengers riding in harnesses that keep them tethered to the helicopter. This allows them to freely take photographs without falling out. These harnesses played a critical role in the accident.

The problems began when a passenger’s tether(some sources report that it was passenger’s bag) slipped beneath the fuel shutoff lever and pulled on it. The pilot began seeking a place to land as the engine died and did not realize that the shutoff had been pulled.

He considered landing in central park but decided there would be too many people around. Instead, he made his way to the river and inflated the floats designed to allow the helicopter to land on the water.

As he prepared for the landing he realized that the fuel shutoff had been activated and began a restart. The timing was wrong though and the engine would not restart fast enough. He followed the procedure and shut the fuel off again just before impact.

I say “impact” because you can see in the videos of the crash that the helicopter did not land gently at all. This could be because of a poor autorotation, or just because there was not enough energy available to begin with.

After landing the helicopter began rolling to the right and was quickly upside down. This is one of the parts that upset me the most because these floats are designed to keep this from happening. However, a malfunction caused the right side floats to not inflate properly!

As it hung under water the skids were the only thing visible. The pilot was unable to free anybody else and he was picked up by a boat responding to the emergency. A big part of this tragedy was the harness system that held the passengers trapped underwater. The tour company supposedly instructed passengers that they were to use a knife attached to the harness to cut themselves free in an emergency. This obviously was not realistic as nobody was able to do it, including a firefighter who was among those lost.

A Chain of Questions

An accident like this produces more questions than answers because there are so many things that went wrong, and if just one of them had gone right these people would still be alive today.

  • Why was the tether able to get around the fuel shutoff?
  • Why didn’t the pilot realize this had happened?
  • Why didn’t the pilot choose a landing on solid ground?
  • Why was the water landing so rough?
  • Why did the pilot not allow the engine to continue its restart?
  • Why didn’t the floats inflate properly?
  • Why were the passengers unable to free themselves?
  • Why was the pilot unable to free anybody?


There are a number of things that could have changed the outcome. In this case, the biggest part of the accident chain was built into the company’s operation with the tethered harnesses. But if the floats had functioned this would not even be considered.

It is important to reflect on these accidents even if it may be difficult to stomach. As pilots, we have a grave responsibility for the safety of others. This is why everything must be done with seriousness and absolute professionalism.

I pray for all those involved in this terrible tragedy.


IMPORTANT: Please read my disclaimer below about accident studies


This study and all accident studies are not meant to judge anyone, their actions, or their skills as a pilot. I do not claim to know what the pilot did or what he/she was thinking. The purpose of these accident studies is to better understand what causes accidents and how to avoid them. Comments and other points of view are always welcome as long as they are respectful towards everyone involved.

Think like a Glider Pilot

Recently I was flying a Piper Arrow at 2500 feet in turbulent air. I was carefully maintaining my altitude with pitch and trim changes. It was a bumpy ride but it was nice watching the puffy cumulus clouds pass by overhead.

Then I began to notice my indicated airspeed was changing despite my unchanged engine settings. First, my speed would be up about 10-15 knots for a minute or so, then it would drop back down for another minute. The next minute it was back up.

Why was this happening?

I thought about it for a few minutes. The engine RPM and manifold pressure were constant, and my altitude was constant.

This could only be caused by updrafts and downdrafts! Yes, the same turbulent air that was creating those clouds was pushing the plane up every time I passed under one.

You can imagine my plane flying in that mass of rising air, and me correcting almost subconsciously to maintain altitude. As the air mass rises, I need to pitch down to stay at the same altitude. This is as good as descending as far as airspeed is concerned.

These updrafts are what glider pilots use to stay airborne and even climb without an engine. A single-engine plane is far too heavy to stay aloft on the updrafts alone, but they do offer us free airspeed which can save on rental or fuel costs.

But how do we take advantage of them?

First, there is terrain: When you have any kind of terrain plan to stay on the upwind side as much as possible. As the wind reaches rising terrain it will rise to go over it and this rising air provides a great updraft that you might be able to take advantage of by altering your course just a little.

Second is cloud streets: Puffy cumulus clouds are formed in rising air so alter course slightly if it will put you under some cumulus clouds. It may be bumpy but if you are between clouds the air will generally be descending to replace the rising air under the cloud. Glider pilots look for cloud streets, which are long rows of clouds that can provide an updraft over a very long distance.

Just think like a glider pilot and consider how the air around you is moving. Tailwinds get all the attention when looking for bonus performance from the environment, but a nice updraft can help any aircraft to go just a little bit faster for the same power.