Topic: Hydraulic Fluids in Aviation

In summary: The main reasons for the different fluids are listed as follows:- MIL-H-83282 has additives to provide the required viscosity and anti-wear characteristics, which inhibits oxidation and corrosion.- MIL-H-83282 has a synthetic hydrocarbon base and contains additives to provide the required viscosity and anti-wear characteristics, which inhibits oxidation and corrosion.- Commercial airlines probably get exactly the same fluid for a lower price, but with a different standard and part number.
  • #1
AeroGeek
12
1
Hello,

We all know that, in Commercial aviation, we use Hyjet (SKydrol or 500B4). and in military we use MIL-H-83282 (red oil). what are the main reasons?

MIL-H-83282 has a synthetic hydro carbon base and contains additives to provide the required viscosity and anti wear characteristics, which inhibits oxidation and corrosion. and having a temperature range of -40 Deg C to +135 Deg C, and its a fire resistant fluid.

Why are we not using MIL standard fluid for Commercial aircraft?
What are the defined standards for Hydraulic systems in Commercial and Military? (where can i get that info. CS/FAA-25?)
Difference in Properties of both fluids?

Thanks in Advance.
 
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  • #2
There are many different standards. You must use the approved fluid. How could you know that two fluids specified in different standards were not the same ?
Anything MIL spec wil be more expensive because the taxpayer pays the bill.
Commercial airlines probably get exactly the same fluid for a lower price, but with a different standard and part number.

https://en.wikipedia.org/wiki/Hydraulic_fluid#Aircraft_hydraulic_systems

http://www.shell.com/business-customers/aviation/aeroshell/knowledge-centre/the-aeroshell-book/_jcr_content/par/textimage_1433441235.file/1445042942924/6c2cb5c8f66a346239c3d2d57412b07f/aeroshell-book-6hydraulics.pdf
 
  • #3
Thanks for the reply. Actually, the two specified fluids are not the same. I'm working in this area currently. we use red oil for military and hyjet for commercial. Both have different properties, i think. While we handle those fluids, we use different set of gloves for each type and different care. Thanks for the manual info book. i'll dig into that and observe the differences and post back the reasons.
 
  • #4
The reason why Hyjet is used in commercial sector is because of its inflammable properties upto 1600 C. and its auto ignition point is about 400 0 C. While Red Oil or MIL-5606/83282 has a lower flash point of about 940 C. They use red oil in military sector because of the confidentiality in technologies and gathering information.
 
  • #5

1. What is the purpose of hydraulic fluids in aviation?

Hydraulic fluids are used in aviation to transmit power and motion through hydraulic systems, which control important functions such as landing gear, brakes, and flight control surfaces. They also help to reduce friction and wear in these systems, ensuring smooth and efficient operation.

2. What are the main types of hydraulic fluids used in aviation?

The two main types of hydraulic fluids used in aviation are mineral-based and synthetic-based fluids. Mineral-based fluids are made from petroleum products and are less expensive, but they have a limited temperature range and can be flammable. Synthetic-based fluids are more expensive but offer a wider temperature range and better resistance to fire and corrosion.

3. How often do hydraulic fluids need to be changed in an aircraft?

The frequency of hydraulic fluid changes in an aircraft depends on factors such as the type of fluid used, the operating conditions, and the manufacturer's recommendations. In general, mineral-based fluids should be changed every 2-3 years, while synthetic-based fluids can last up to 5 years.

4. How do hydraulic fluids affect the performance of an aircraft?

The quality and condition of hydraulic fluids can greatly impact the performance of an aircraft. Contaminated or degraded fluids can lead to malfunctions in the hydraulic system, resulting in loss of control or other safety hazards. It is important to regularly check and maintain the hydraulic fluids to ensure optimal performance of the aircraft.

5. What are the safety precautions for handling hydraulic fluids in aviation?

Proper safety precautions should always be taken when handling hydraulic fluids in aviation. This includes wearing protective gear, using proper storage and handling techniques, and following manufacturer's instructions for disposal. It is also important to regularly check the fluid levels and condition to prevent any potential hazards or accidents.

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