Accumulation of aircraft anti-icing fluid (SAE type iv) on runways - Civil Aviation Safety Alerts (CASA) No. 2013-05


Airport operators with aircraft De-icing facilities accumulation of aircraft anti-icing fluid (SAE type IV) on runways

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Issuing Office: Standards Branch
Document No. : CASA -2013-05
File Classification No. : Z 5000-35
Issue No. : 01
RDIMS No. : 8277446
Effective Date: 2013-09-20


The purpose of this Civil Aviation Safety Alert (CASA) is to highlight a potential risk of increased accumulation of aircraft anti-icing fluid (SAE Type IV) on runway thresholds from aircraft ground anti-icing operations.


Transport Canada has received a report from a Canadian airport operator experiencing an increased accumulation of aircraft anti-icing fluid (SAE Type IV) on the runway threshold area.

This issue has been observed by the airport operator since the introduction of a new SAE Type IV fluid, approximately 4 years ago. SAE Type IV fluids are viscous and designed to shear off as the aircraft accelerates during the take off run. Previously, maintenance personnel noticed some deposition of the anti-icing fluid on the taxiways but less on the runway. However, the dye used in the new fluid makes it more visible than previously even when the same quantities are present.

The SAE Type IV fluid deposited on the runway may cause snow to melt and change the reported surface conditions. Loose blowing snow may adhere to the anti-icing fluid, increasing the accumulation of snow on the runway. This effect may eventually create slush and ice conditions, resulting in lower friction values in the first third of the runway. This effect is dependent on weather conditions and amount of traffic.

If the runway is used for mixed operations (both takeoffs and landings), this may create an increased risk for landing aircraft.

In order to address the reduction in runway friction values in the first third of the runway, the frequency of runway sweeping had to be increased.

Recommended action:

Airport operators should be aware of this potential issue and the resulting additional airfield maintenance that may be required. In addition to runway sweeping, the application of acetate or formate based runway ice control chemicals to the area where the anti-icing fluid is deposited may eliminate or reduce the accumulation of the anti-icing fluid.

In order to document if this issue is encountered at other airports, Transport Canada encourages airport operators experiencing similar issues with increased anti-icing fluid (SAE Type IV) accumulation on the runway threshold area, and slush and ice conditions caused by blowing snow adhering to the fluid, to report this to the contact office given below.

Contact office:

For more information concerning this issue, contact Mr. Guy Héneault, Program Manager, Aerodrome Standards, Flight Standards in Ottawa, by telephone at 613-991-9939 or by e-mail at

original signed by Arlo Speer for

Aaron McCrorie

The Transport Canada Civil Aviation Safety Alert (CASA) is used to convey important safety information and contains recommended action items. The CASA strives to assist the aviation industry’s efforts to provide a service with the highest possible degree of safety. the information contained herein is often critical and must be conveyed to the appropriate office in a timely manner. The CASA may be changed or amended should new information become available.