Is that gasoline I smell?

Text: Webmaster Leo
Images: Henk Dumont & Leo LLama
Animal images: wikipedia public domain

Are you an owner, pilot or co-pilot of a Valentin Taifun 17E II ?
Then you should definitely read this article. Maybe you can prevent a dangerous situation and a lot of work too.
Even if you own another type of airplane it's worthwhile reading, you never now when an accident is going to happen!
An interview with a Taifun 17E II owner:


Henk Dumont:
"It was during early spring 2005 when I experienced a weird phenomenon on several pre-flight preparations with my Taifun 17E II. Every time I pulled the motorglider out of the hangar and opened up the canopy, I sensed some gasoline-like smells which seemed to emerge out of the cockpit. I never noticed this after ending a flight, there were no visible gasoline patches on the floor and during flight this gasoline-like smell gradually tended to disappear.
At first I thought it was only my imagination deceiving me, but after some weeks the intensity of the gasoline smell seemed to be increasing.

The first two or three times I paid few attention to this and supposed it would be some gasoline remainders left behind by some motorplane also kept in the same hangar. After a few weeks, as said before, I was very sure it was my own plane that smelled like gasoline and unwittingly I had to think of this WWII single person submarine I once saw at the Berlin Museum of Technics. The so called "Biber" (German for Beaver) U-boat had a death rate of nearly 30% of its personnel because of shortcomings on the engine exhaust system which caused noxious gasoline fumes and carbon monoxide to stay inside of the boat hereby suffocating its captain and only crew member.

Biber, German WWII 1-person, 2-torpedo U-boat at the Deutsches Technik Museum Berlin
Lots of captains did not return from their mission because of CO-suffocation.

Choked to death?
Thinking of the Biber-story I imagined myself becoming unconscious during flight as an effect of the gasoline fumes inside my Taifun. I assumed that during flight the fumes appeared to decrease in intensity because my organs of smell got accustomed to all the fumes around my head. When you're being surrounded long enough by the same smell, after some while you don't smell anything anymore. Definitely a dangerous situation, so I decided to investigate the cause of this smell.

Because I could not find anything unusual near the engine, I first had this feeling I had to look at the fuel cock. Underneath the co-pilot's seat there a cock, operated by a lever on the panel, which can be used in case of fire in the engine. By shutting the cock and thereby ceasing the feed of fuel to the engine, the fire will be extinguished after a while by lack of fuel. For safety reasons this cock must be replaced every 5 years. Mine wasn't that old, but perhaps there was some kind of leak or puncture near the cock that caused gasoline damps to spread into the cockpit. Anyway, after a few hours of disassembling the co-pilot's seat and looking and sniffing around, I found nothing suspicious. No leaks or punctures near the fuel cock, no sign of gasoline patches, no liquids underneath the seat or near the fuel cock. A bit angry, but confused at the same time, I assembled the seat again and went home with a puzzled mind.

Found it!
Next week when I pulled out the Taifun for a new flight, the smell was even worse than ever before. It was very obvious this time that it had to be something inside of the cockpit, because outside of it, or near the engine, there were no fumes at all. I wisely decided not to fly and instead I disassembled the entire cockpit, including floor and seats. Loosing a lot of sweat and at the same time inhaling horrible gasoline fumes, after an hour of two I discovered something I will never forget the rest of my life. Underneath the pilot's seat there's a flexible hose that leads the fuel from the left wing tank to the engine. On three different spots each fairly close to one another, the hose was damaged and several drops of fuel had been spilled on the floor.

View underneath the pilot's seat.
I put a small cylinder under the black hose in the middle to catch the leaking fuel.
Picture made on May 18th 2005, after weeks of searching for the cause.

 

The same fuel hose, with three clearly visible damaged spots, pictured on the wing of my Taifun.

stone marten (sometimes also called beech marten)

Who dunnit? After examining the damaged spots on the hose I wondered what kind of animal had gotten into my plane and caused these small holes in the fuel hose. Around the area where I live stone martens biting through fuel houses of cars at night is a common thing, so I presumed it to be a marten that caused this fuel damps in my cockpit. Since I was curious I sent the hose to the German TÜV (Technischer Überwachungs Verein, German meaning Technical Monitoring Association) and they examined the bites in the hose.

 

Bite marks of some kind of rodent in close-up. Hose diameter is about 1 centimetre (0.4 inch)

 

A hose mouse After a week or two the TÜV returned my hose with a report stating that after examining the bitemarks very carefully they concluded that the marks were not caused by a stone marten but by some sort of mouse, probably by a house mouse. Korff Company also has made a technical report at their Luftfahrt Technischer Betrieb (Aeronautical Engineering Department). Afterwards I had to laugh about this tiny animal that caused such a large machine to stay aground, but I think they had better given this rodent a different name. Instead of house mouse they'd better call it a hose mouse !

House mouse (Mus musculus)

How did it get in?
Now that I knew what had caused the fuel hose to become leak I wondered how the mouse got into the cockpit, so perhaps I could prevent future leakages. After examining the airplane I concluded there was only one way for the mouse to get into the cockpit and that was via the landing gear. This route can only be made on a Taifun 17E II, since the 17 E I fuselage is shut off the outside world when the landing gear is out. The mouse must have pulled itself up along a cable at the gear and in between the tubes into the fuselage and the cockpit (see images below). It's common knowledge that mice search for hot areas in wintertime so this one probably got into my Taifun after some flight when motor, fuselage and cockpit were still radiating heat into the cold hangar, which must have attracted the mouse to make a real Tour de Force to get into the cockpit.

A real Tour de Force for a mouse, yet it has been proven to be possible.

A simple solution Since I wanted to prevent mice from getting into my plane anymore, I constructed some sort of funnel, made of aluminium, which can be folded easily around the landing gear to withhold mice from passing by. You can easily make this kind of funnel for any airplane, just by cutting an aluminium strip that's wide enough, and folding it around the landing gear. The strip is then taped with any kind of (smooth) adhesive tape. Of course I replaced the broken hose with a new one and the problem was fixed. Since then no mouse has ever entered my cockpit again. The only animal ever to fly in my Taifun has been a Llama (Leo Llama to be exact).

My advice
I do sincerely hope no reader will ever experience this kind of disturbance of domestic peace. Make some funnels yourself and your plane will be free of mice and other rodents.

Have a safe flight!"

Henk "the flying Dutchman" Dumont
(as interviewed by webmaster Leo)

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