Fuel Hoses

Hi Roger,

"...........don’t forget fuel and oil hose belong in protective fire sleeve"

So where is the empirical evidence for this advice?

My subjective opinion: If and only if, the fire sleeve has been installed to aircraft certified standards, might it have some modest benefit in an engine fire situaton.

As for thermal insulating, again a slight benefit for hoses impacted by radiant /convective heat  - primarily over engine hoses and an on ground issue (fuel vaporisation).

From my jaded perspective, its primarily an aesthetic enhancement, bit like go faster stripes😈

Hi Sean,

It’s been around for decades. It’s a standard in the US and other places. The last thing you want is an engine fire and have fuel and oil hose ruptures and then feeding a fire up to 1800F - 2000F. You don’t want hose close to a hot exhaust pipe rupturing because it’s not protected.

“Have you heard of fire sleeves? They are commonly used in airplanes. As shown in the adjacent photo, fire sleeves consist of a hollow, sleeve-like tube. For a better understanding of fire sleeves, including why airplanes have them, keep reading.

The Basics of Fire Sleeves

Fire sleeves are tubes made of fire-resistant materials. They are designed to protect wires, cables and hoses from fire damage. Some of the first fire sleeves emerged in the 1970s, during which they were used in military airplanes. In the years to follow, fire tubes made their way into the commercial and private aviation industries. 

While available in different types, most fire sleeves aren’t made of a single material. Rather, they are made of multiple materials. They are constructed of a heavy-duty material, which is then surface-treated with one or more other materials The inner core of a fire sleeve may consist of fiberglass. Surface treatment materials, on the other hand, may consist of synthetic rubber or natural rubber.

Aside from their fire-resistant design, fire sleeves are flexible. They can flex and bend without breaking. The flexible properties of fire sleeves allow for easier installation. Aerospace manufacturers and technicians can run fire sleeves around corners and through tight spaces without fear of breaking them.

Why Airplanes Have Fire Sleeves

Fire sleeves offer protection against fire damage. Wires, cables and hoses can all fail when exposed to heat. The heat from a nearby fire can burn through wire and cable jackets, thus damaging the conductors. Fire sleeves are designed specifically to withstand heat. 

Some of them are even classified as incombustible. Incombustible fire sleeves won’t burn or otherwise combust when exposed to a flame. They are rated to withstand temperatures of up to 500 degrees Celsius.

In addition to cables and wires, fire sleeves are used to protect hoses from damage. Airplanes, of course, feature many different hoses, including fuel and oil hoses. Fuel hoses carry jet fuel, whereas oil hoses carry lubricating oil. Some manufacturers encase fuel and oil hoses in fire sleeves. Fire sleeves will shield the fuel and oil hoses so that they are protected from fire damage.”

Roger, 

As I said CERTIFIED INSTALLATIONS or instalatons using certified techniques - and even then, likly to only add a few seconds/perhaps a minute or two before the engine falls out of the aircraft.

Most fire sleeves, that I see, have the fuel/ oil hose exposed at both ends, or a bit of tape wrapped around to provide an aesthetic finish - in practical terms, almost useless.

I would go so far as to say, push on hose + fire sleeve, only has some some heat insulating benefit and almost nil fire resistance.

Sure! if there is no alternative to routing a hose (oil, fuel coolant) or electrical cabling away from a high heat source (usually the exhaust system) it is good practise to have some sort of temperature shielding. In normal operation, this will protect the vulnerable system from radiant/convective & to some degree conductive heat. It will do almost nothing in a fire situaton.

In light recreational/sport aircraft (non certified), the main benefit of fire sleeve seems to be  bragging rights.

Thank you all guys! I will dive into the info you posted and use it to buy one of the recommended hoses.
My Tecnam P92 has never had the original Rotax hoses, which makes it much cheeper to replace. And, yes I am from Israel and we have a Rotax supplier that will be happy to sell me the Rotax original for a fistful of dollars (-;

I will stay with what Tecnam installed.

Hi all

I dug up an old picture and put on a few comments.  If you want to get full copy you have to buy the document from SAE, look for:

TSO C53a for fuel and oil lines

Cheers