Student Pilot Emergency Landing - Didn't Switch Fuel Tanks

[okgood]

It seems like a design flaw to me, to have to remember to switch fuel tanks every 30 minutes. What do you think?

 

VERO BEACH, Florida - On December 2, 2019, a Piper PA28 Warrior, N558PU, was substantially damaged during a forced, student pilot emergency landing in a field. The student pilot was not injured. The pilot departed VRB earlier in the day for a solo, cross-country flight. He took off from VRB with full fuel tanks and landed uneventfully at another airport. He intended to switch fuel tanks one hour into the flight, contrary to the flight school's policy of every 30 minutes. He forgot to switch tanks prior to landing at the other airport and did not switch tanks on the ground prior to departure. During the return flight to VRB, he again did not switch fuel tanks. While in the traffic pattern at VRB, the engine lost all power and quit. Unable to glide to runway 4, he performed a forced landing in a field to the south of the airport. During the landing roll, the airplane collided with a tree, separating the left wing from the airframe. Both wings and the fuselage were structurally damaged. The left wing fuel tank was not breached and contained no fuel. The right wing fuel tank was completely full of fuel. The cockpit fuel selector handle was found in the left tank position.The 22-year-old student pilot seemed stunned and without words.

 

 

 

[Thruster88]

It seems like a design flaw to me, to have to remember to switch fuel tanks every 30 minutes. What do you think?

 

 

Obviously not everyone is PIC material. A fuel log is not that onerous, changing tanks and fuel pump on is a memory item in the case of engine failure, the engine would have resumed normal operation.  

 

 

[okgood]

Agreed. I learned in a high-wing, so the fuel was gravity fed from both tanks, but even on my emergency checklist there was a step to ensure the fuel selector switch was turned to BOTH. I realize he may not have had much time, especially if the engine quit at low altitude, but from the report it seems he didn't switch the tank at all during his touch-and-go practice at some other airport.

 

 

[facthunter]

You are not supposed to let the fuel levels get out of balance either. Something wrong with the training there. Nev

 

 

[KRviator]

You are not supposed to let the fuel levels get out of balance either. Something wrong with the training there. Nev

 

Some aircraft have that as a limitation, but typically not at our level. My usual practice is to takeoff and climb to cruise on one tank, change to the other and let it run dry (~ 165 minutes), then change back. 

 

I've minimised the chance of an issue with the fuel valve, even though they are statistically rare, I've minimised the chance of forgetting to switch tanks, and I have a known quantity of fuel on board at any time based on nothing more than my watch.

 

 

[tafisama]

I agree with the above comments,the safest way should be to have off and on only.However the feed lines should be fitted with non return valves so that no tank is fed in during banking.

 

 

[facthunter]

Having experienced the difference when test flying a side by side plane of flying it from both seats  I would think you certainly are going to affect any (small) plane that has something like a 40+ Kilo difference in fuel load from one wing to the other, in the way it flies.

 

    I can see you simplify your fuel management actions with your method  but any Pilot should monitor the fuel situation regularly during the whole flight. Your engine could be using fuel at a higher rate than it has previously and/or there could be a leak or venting somewhere.... If you observe something irregular, then you can take appropriate actions  and usually the earlier they are done the more effective they will  be. I'm not saying you can't fly a plane with one wing full and the other empty but it must affect how it flies particularly when landing and  fuel balance is a good thing to consider at all times as GOOD PRACTICE.  My comment "something wrong with the training there" was inattention to the fuel monitoring" and lacking of awareness that produced the inevitable result. Engine starved of fuel while he still had 1/2 of it on board. Fuel management varies from plane to plane and the design of the fuel system. A good system would allow the last drop to be reliably used  every time without any chance of introducing air into the system. One way of achieving that is N/R valves to each tank outlet and a" Both ON" position and tank boost pumps. Nev

 

 

[kgwilson]

Sounds like the student was a bit of a know it all. Ignoring the flying school policy of changing tanks every 30 minutes, not keeping a fuel log & failing to check & switch tanks when on the ground. All simple and standard procedures. PA 28s have been around for a very long time and many thousands of pilots have not had problems as they adhere to the operating procedures. Based on the accent I wonder if the student was training to eventually become an airline pilot in Asia. If so this event should convince him to change his career options.

 

 

[GraemeK]

The POH for the Warrior recommends running on the first tank for 1 hour, then second tank for two hours, then back to the first (assumes tanks full initially, each tank roughly 2.5hr).

 

I usually follow that recommendation.

 

 

[Thruster88]

The pilot did do one thing right by only removing the wing with no fuel.

 

[KRviator]

A good system would allow the last drop to be reliably used  every time without any chance of introducing air into the system.   

 

You'll find certification (FAR 23.955) requires a tank to be able to be run dry and then, on switching tanks, have 75% MCP available within 10 seconds. Or 20 seconds for turbocharged birds. Granted ours aren't usually certificated to such a standard, but a prudent owner will test both minimum usable fuel and the behaviour of the engine in a dry-tanks scenario. 

 

Here's what happens in my RV-9A when you do so - though I'd already tested this in a safe spot before incorporating this as a standard practice. Don't do it for the first time over tiger country! 

 

 

 

 

 

 

[Thruster88]

I agree with the above comments,the safest way should be to have off and on only.However the feed lines should be fitted with non return valves so that no tank is fed in during banking.

 

Because the fuel is SUCKED from the tanks in a low wing both is not an option. If one tank gets empty air is easier to suck than fuel resulting in engine stoppage. Both works fine in a Cessna 172 because ONLY gravity is used to get fuel to the carbureter.  

 

 

[facthunter]

I mean... be able to  get the last drop of ALL the fuel IF that's where you end up. Sometimes the" not reliably available" can be a considerable amount., and the fuel you plan (with required reserves) on must be based on a figure that does exist. "Useable Fuel" I would never run an engine out of fuel deliberately. It's not easy on them and just putting fuel back in is not the way to go, for pistons and particularly turbines.

 

 Regarding thruster's comment which I believe was directed to me. All boost pumps ON and system common will allow no air to enter the system until all tanks are empty AS while ANY pump has fuel and is not cavitating the empty tank N/R valves will be closed and stop any air entering the system and THAT tank where the pump has pressure will supply the system till the fuel is exhausted .

 

 As Thruster points out if the EDP is sucking fuel it will pull air into the system before an alternative fuel supply and may make it difficult to be purged from the system quickly enough to restore power in the time available . Nev

 

 

[Thruster88]

My comment was not directed to you Facthunter, but we are talking simple aircraft with only one boost pump and one engine pump plumbed in series sucking from two tanks. 

 

Running a tank dry which I have done because I am a curious George and for operational reasons when I wanted the 30 od litres remaining  to all be in one tank will not hurt a Lyc 0-320, instructors pull the red  knob all the time to simulate engine failures.

 

 

[facthunter]

You will/can  get all kinds of systems potentially and there's maintenance issues as well affecting reliable fuel flow. Kinked lines, heat causing vapour lock , water drain location, Firewalls, filter restrictions, vent problems etc. I TRY to talk in principles, not specific fuel systems as there's so many possible variations. It's an issue worth  exploring due to the safety aspect of getting it right or maybe coming unstuck..like happens a lot these days .

 

  In response to your edit pulling the red knob" Fuel cut out" is quite a different thing to running the tank and the whole fuel line and engine driven pump, dry. You get a pretty clean cut and the restoration of power is pretty definite also. .Nev

 

 

[pmccarthy]

An old Comanche with tip tanks was hard to manage, no gauges on those tanks. They would often run dry and then you had a quick changeover.

 

 

[poteroo]

Here's what happens in my RV-9A when you do so - though I'd already tested this in a safe spot before incorporating this as a standard practice. Don't do it for the first time over tiger country!

 

 

 

Quite a number of RVs have been built here, and I've done quite a few of the initial flights and test programs. In order to get a good fuel tank calibration it's been my practice to run one tank dry in flight, then refill it from the bowser and run the Dynon, (or other EFIS), calibration. Once you recognise the loss of power, tanks can be switched even without electric pump being used. Picks up in 5-6 secs.

 

happy days,

 

 

[Downunder]

My experience and testing on  Rotax high wing. 2 wing tanks. One isolation valve per tank. No electric pump.

 

If running one tank dry, fuel will NOT pick up and flow after opening the full fuel tank. Only after closing the empty tank.

 

The engine pump will prefer to suck air than pick up fuel so the empty tank needs to be immediately closed.

 

There was a crash of a Flight Design in the UK where one tank emptied (the other had fuel) but because they only have one isolation valve after the tanks joined it was impossible to shut off the empty tank. The engine could not be restarted and it crashed.

 

 

[Mike Borgelt]

The tanks will only cross feed on BOTH if the ball is out of the middle. Banking is irrelevant if the ball is in the middle. Some more revision on aerodynamics is indicated for some people.

 

 

[Raytol]

I flew an ASW-19 with one water ballast tank full and the other one empty to see what would happen.

 

There was no discernible difference in flight characteristics but on landing, as I slowed down, I could not hold the heavy wing up with aileron.

 

This lead me to think that the load is distributed across the wingspan and the concentration of load is also somewhat spread along the wingspan.

 

This is why pilots can't feel the fuel tanks levels. I guess that is why they put gauges in the tanks to measure the fuel levels!

 

 

[Mike Borgelt]

I had a dump failure on one side in my mini Nimbus once. Could only tell on the ground roll when the wing dropped. The earlier gliders had the ballast tanks pretty close to fuselage and the ailerons a long way out so that might explain it.

 

However in our BD-4 it gets uncomfortable holding aileron in the event of tank imbalance. Might also run out of aileron in crosswind landing so I try to balance by burning 30 minutes a side then switching tanks.

 

 

[poteroo]

The tanks will only cross feed on BOTH if the ball is out of the middle

 

Which is why many pilots complain that Cessna 100 series aircraft can't be flown on 'BOTH' without tanks draining unevenly.  Good indicator to instructors that student isn't in balance.   Happy days,

 

 

[facthunter]

The Gazelle is the same . Funny how it only happens with some pilots but the vents can cause it .

 

If the cap isn't secure , some Cessna's will suck the rubber tank  out of shape and vent most of the fuel and still show fuel on the gauge when it stops feeding. Nev

 

 

[KRviator]

If the cap isn't secure , some Cessna's will suck the rubber tank  out of shape and vent most of the fuel and still show fuel on the gauge when it stops feeding. Nev

 

I hadn't heard that before. I can understand if the vent was blocked, with fuel being drawn normally, as that's caused several incidents before too (including in the RV world) but do you know why it'd distort the bladder as well as dumping the fuel overboard just by leaving the cap off?

 

 

[Orf]

My check list says to select the tank with the most fuel for take-off. A rule you break at your own risk.