A I R C R A F T C A B I N A I R Q UA L I T Y B R I E F // J ULY 2 0 2 0
A IR M A NAGEM ENT
SYSTEM S
Essential systems for a safer,
more comfortable flight
I NT R O D U CT I O N
Collins Aerospace is a leading supplier of aircraft
environmental control systems (ECSs) for military and
commercial transport, which include the ATA Chapter
21 systems for air conditioning, ventilation and cabin
pressure control systems. Collins Aerospace is pleased
to provide this brief summary regarding information
on aircraft cabin air quality, with specific emphasis
on contamination originating from inside the cabin.
A list of noted reference material can be found at
the end of this summary.
Three main characteristics of cabin air management
systems help mitigate the spread of airborne pathogens
within a typical ECS:
1) Fresh air inflow regulations
2) High efficiency particulate air (HEPA) filters for
recirculated air
3) Airflow distribution design in an aircraft cabin
2
Air Management Systems | July 2020
A H IG H E R FI LT R ATION STA NDA R D
F O R A I RC R A FT CA B IN A IR
F R E S H -A I R I N F L O W R E G U L AT I O N S
H E PA F I LT R AT I O N O F R E C I R C U L AT E D A I R
Aviation regulatory authorities such as the Federal Aviation
Administration and European Union Aviation Safety Agency
specify a minimum outside fresh airflow per occupant, based
on the maximum number of occupants (0.55 lb./min. of fresh
airflow per occupant)1. In a large commercial passenger aircraft,
for example, a typical ECS that adheres to this specification
may replace the air occupying the cabin within about 3 minutes,
or about 20 changes per hour of the air occupying the cabin.
This may vary slightly by aircraft, based on several factors
such as the ratio of maximum passenger capacity to total cabin
volume, and distribution system layout. By comparison, the
general guidance on fresh air inflow for buildings is only
four changes per hour2.
In some aircraft ECS designs, approximately 50% of the airflow
within the cabin is recirculated and mixed with the outside fresh
air flowed into the cabin. In some cases, the recirculated air
passes through a HEPA filter prior to mixing fresh air with
recirculated air. HEPA filters are commonly considered to be
an effective way to mitigate virus transmission3 and are used
in hospital protective environments4. For comparison, HEPA
filters can have a higher filtration efficiency (99.97%) than an
“N95” respirator (95%)5. As is common for larger commercial
aircraft, Collins Aerospace products include HEPA recirculation
filters as part of the ECS on many platforms such as the Boeing
787. While HEPA filters are common, there may be some older
and/or smaller aircraft platforms that do not have HEPA
filtration. However, in many cases, there are OE and retrofit
products available6.
Air Management Systems | July 2020
3
CABIN AIR
QUALITY IS
CRITICAL TO
PASSENGER
SATISFACTION
CABIN AIRFLOW DISTRIBUTION
Aircraft cabin air distribution systems often are designed
to distribute the airflow from high (crown) to low (floor
vents), and not from the front to back of the cabin. One of the
reasons for this design is to manage emergency situations such
as smoke events to ensure smoke does not permeate throughout
the aircraft cabin7. This design has the added benefit of reducing
the spread of unfiltered, contaminated air throughout the cabin,
but it does not eliminate the risk completely8.
Collins Aerospace’s air management systems are
designed to meet customer requirements for efficiency, reliability, weight, performance, safety and maintainability.
We offer advanced air management systems that enable
a safer, healthier and more comfortable environment
during flight.
V i s i t co ll i ns ae r o s p ace .co m to l e ar n m o r e
Airbus A380 Air Generation Unit
Boeing 787 Electric Air Conditioning Pack
R E F E R E N C E S A N D A D D I T I O N A L P U B L I C I N F O R M AT I O N S O U R C E S
1.
2.
3.
4.
5.
Federal Aviation Administration Regulations, 14 C.F.R. § 25.831(a); European Union Aviation Safety Agency, Certification Specifications, CS-25.831(a)
ASHRAE 62.2-2016
Pall Aerospace website https://shop.pall.com/us/en/aerospace/military-vehicles/cabin-air-filtration/zidgzyl8yrb
American Society for Healthcare Engineering – Hospital HEPA usage in “protective environment“ rooms https://www.ashe.org/compliance/ec_02_05_01/01/airfiltration
FDA website – N95 Respirators and Surgical Masks (Face Masks) https://www.fda.gov/medical-devices/personal-protective-equipment-infection-control/n95-respiratorsand-surgical-masks-face-masks#s3
6. Pall Aerospace website https://shop.pall.com/us/en/aerospace/commercial-fixed-wing/electronics-cooling-filtration/zidgxiyphh4?CategoryName=
Commercial-Fixed-Wing&CatalogID=Aerospace-Defense-Marine&tracking=searchterm
7. Federal Aviation Administration Advisory Circular 25-9A, Jan. 6, 1994.
8. The Airliner Cabin Environment and the Health of Passengers and Crew, specifically the sections on Air Distribution and Circulation, and recirculation
https://www.ncbi.nlm.nih.gov/books/NBK207472/
Collins Aerospace
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fax: +1.860.660.0372
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