PAE 535a

Pall Avionics Cooling Filter Assembly

In modern commercial aircraft, with the increased dependence on electronic systems and fly-
by-wire technology, the avionics (E/E) cooling system plays an increasingly important role in the
overall system reliability. Therefore it is essential that the avionics cooling filtration system is
highly efficient at removing both free water and solid particulates from the cooling air.

For the Airbus A318, 319, 320 and 321 series of aircraft, avionics system cooling air is drawn
from 2 areas:
On the ground, air enters through an inlet located on the forward port side of the aircraft,
whereas in flight, the avionics air system switches to a closed loop re-circulation system.

Features

• Pall Aerospace depth filter medium offering a low differential pressure with maximum
filter service life.
• Demonstrated assembly 100 % water removal efficiency.
• Performance qualified against internationally and Airbus accepted standards.
• Only one disposable element to stock and change.
• Proven performance, installed on over 1500 aircraft worldwide.

Operational characteristics

• Free water entering the avionics bay will potentially lead to corrosion of electrical pins,
connectors and other electronic components. The presence of free water can also cause
immediate electrical/electronic equipment malfunction thus rendering the components
inoperable.

• Free water is removed by use of a patented centrifugal separation assembly, which

provides a one hundred per cent (100 %) free water removal efficiency even under the most
adverse testing conditions. As the water removal system uses centrifugal technology there
is no potential for blockage, therefore the differential
pressure across the centrifuge section of the filter
assembly remains constant. Airbus tested the 'Pall'
system with both clean and fully blocked filter
elements and demonstrated that these had no effect
on the water separation efficiency.

• Clean air is necessary to ensure particulates do not

accumulate on electronics equipment located in the
avionics bay. Particulates can act as insulators so
any accumulation will result in avionics equipment
operating at elevated temperatures, thus the
reliability of this equipment will be reduced.

• Solid particulates are removed from the avionics

bay incoming air by a single disposable filter
element.

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Questions and Answers

Q1 How does the Pall avionics cooling filtration system differ from alternative systems
available?
The Pall system uses a patented centrifugal separation assembly that provides a one hundred
per cent continual water separation efficiency even under the most adverse testing conditions.
The efficiency remains constant and is not affected by the pressure drop across the filter
element.
The Pall system was tested by Airbus, with both clean and fully blocked filter elements
installed. The results demonstrated that there was no effect on the water separation efficiency.
In comparison, the alternative system uses a mesh as a demister and as this element
becomes blocked, the flow velocity through the mesh increases and hence a reduction in the
water separation efficiency is likely.

Q2 How was the filtration removal efficiency of the Pall system tested?
During qualification testing witnessed by Airbus the Pall filter element (QB0639) demonstrated
the following particulate separation efficiencies.
• 100 % with carbon black (size range 0.1 to 5 micron).
• 85 % with silica dust. (size range 0 to 5 micron).
• 87 % with Airbus test dust.

Q3 How does the Pall system compare to the alternative when comparing maintenance and
cleaning?
The Pall system has only one disposable element (QB0639) to replace. The alternative system
has two replaceable elements. Therefore the Pall system offers both time and replacement
costs savings.

Q4 What happens to the water collected in the Pall system?

After the water has been separated by the Pall system, it is drained from the housing via the
trap and non-return valve assembly. This drain system is fitted with a strainer to prevent
blockage of the trap with large particulates.

Q5 What operational experience has the Pall system had?

The Pall system has been in service since 1995. Subsequent to this Pall have now tested
around 100 used filter elements and accumulated a significant amount of worldwide in service
data and experience. The Pall system is fitted on over 1500 in-service aircraft worldwide.

Q6 What is the combined weight of the Pall system?

The Pall system weighs 9.3 Kg. An alternative lighter composite material housing was offered
during the original qualification stages but Airbus declined to pursue this option.

Q7 Is the Pall system approved by Airbus?

Yes, for new build production aircraft it is available as a no charge option (Reference 24146).
Yes, for retrofit of in-service aircraft, it is available via Airbus Service Bulletin A320-21-1087 at
no charge.

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Technical Data

Description
Complete Filter Assembly QB0452
Filter Housing QB0555
Filter Element QB0639
Syphon Tube QB0553
Particulate removal efficiency 85 % with Silica Dust
100 % with Carbon Black
87 % with Airbus Test Dust
Dirt Holding Capacity 829 g Silica Dust
123 g Carbon Black
270 g Airbus Test Dust
Water Efficiency 100 %
Airbus Service Bulletin A320-21-1087
Airbus Modification Numbers 24146, 26739, 27038

Satair A/S Satair Pte. Ltd. Satair USA

Amanger Landevej 147A 27 Loyang Link 3993 Tradeport Boulevard
2770 Kastrup, Denmark 508728 Singapore Atlanta, GA 30354, USA

+45 3247 0100 telephone +65 6543 0977 telephone +1 404 675 6333 telephone
+45 3251 3434 fax +65 6543 0737 fax +1 404 675 6333 fax
+45 4040 1224 AOG Service +65 6543 0977 AOG Service +1 404 310 1966 AOG Service
CPHSA7X SITA SINSA7X SITA ATLSA7X SITA

www.satair.com

Pall Aerospace
Visit us on the Web at www.pall.com/aerospace
10540 Ridge Road
New Port Richey, FL 34654 Pall Corporation has offices and plants throughout the world. For Pall representatives in your
area, please go to www.pall.com/contact
+1 727 849 9999 telephone
+1 800 933 3111 toll free US Because of technological developments related to the products, systems, and/or
services described herein, the data and procedures are subject to change without
notice. Please consult your Pall representative or visit www.pall.com to verify that this
Portsmouth - UK information remains valid.
+44 (0)23 9230 2399 telephone
+44 (0)23 9230 2203 fax © Copyright 2011, Pall Corporation. Pall and are trademarks of Pall Corporation.
aerospace@pall.com ® indicates a trademark registered in the USA. ENABLING A GREENER FUTURE and
Filtration. Separation. Solution.SM are service marks of Pall Corporation.

AEMILVEN Produced in the UK March 2011

PAE 535a Printed in the UK. May 2011