CAR subpart 604, 703, 704 and 705 operators
|Issuing Office:||Civil Aviation (Standards Branch)|
|Document No.:||CASA 2015-06|
|File Classification No.:|
The purpose of this Civil Aviation Safety Alert (CASA) is to alert operators and pilots that Transport Canada (TC) is removing DEFROST ECO 1 (manufactured by Oksayd Co. Ltd.) from Table 8-1 of the 2015-2016 Holdover Times GuidelinesFootnote 1.
TC has recently been made aware that this fluid contains alkali organic salts (AOS). These are chemicals that may pose a significant safety hazard given their impact on anti-icing fluid (Type II, III and IV) performance and their published holdover times.
At the time of this publication TC has no knowledge of this fluid being available in Canada. This CASA serves as an awareness tool to all stakeholders with recommended mitigation strategies and also reminds the reader to be aware of the potential availability of these fluids in foreign markets.
Most non-thickened (Type I) deicing fluids contain Ethylene Glycol (EG) or Propylene Glycol (PG) as the main freezing point depressant within their formulation. In more recent years some fluid manufacturers have sought to produce non-glycol based fluids containing other chemicals such as AOS that offer the same freezing point depression characteristics while reducing some potential negative impacts inherent with EG or PG bases (e.g. environmental degradation).
AOS can significantly accelerate the degradation of thickening agents contained in anti-icing fluids resulting in a reduction of an anti-icing fluid’s viscosity and holdover time.
Although this fluid meets various standards and specifications published by the Society of Automotive Engineers (SAE) including those in Aerospace Material Specification (AMS) AMS1424L Deicing/Anti-Icing Fluid, Aircraft, SAE Type IFootnote 2, this fluid contains AOS. The SAE is currently reviewing the applicable standard to establish a composition of matter requirement of de-icing fluids.
This action is substantiated through previous research carried out by TC and the Federal Aviation Administration (FAA) that examined the impacts of runway deicers (containing AOS) on anti-icing fluids and is addressed in TC’s Guidelines for Aircraft Ground-Icing Operations (TP 14052E, Second Edition, April 2005)Footnote 3
Directors of safety, directors of operations, chief pilots, check pilots, pilot instructors, training providers and service providers should ensure that all staff involved in ground icing operations are aware of the update to the 2015-2016 Holdover Times Guidelines.
Only the de/anti-icing fluid Types (I, II, III, IV) approved by the airplane manufacturer should be applied to the airplane.
It is preferable that operators avoid the use of any de-icing fluid containing AOS. In operational situations where this may not be possible it is advisable to pay special attention to the amount of anti-icing fluid used in a two-step de/anti-icing process. In a two-step operation, an application of de-icing fluid removes any contamination on the aircraft surface. This is followed-up by a second step application of an anti-icing fluid which washes off any remaining de-icing fluid. The anti-icing fluid remains on the surface to protect the aircraft from additional contamination during its holdover time.
To mitigate any risk posed by a AOS-containing Type I fluid, special attention should be given to ensure that a sufficient amount of anti-icing fluid has been applied to ensure complete removal of de-icing fluid so that the anti-icing fluid will have its appropriate holdover time. SAE Aerospace Recommended Practice ARP4737H, Aircraft Deicing/Anti-Icing MethodsFootnote 4 provides guidance and methodologies to this effect.
For more information concerning this issue, contact Mr. Roman Marushko, Program Manager, Flight Technical and Operator Certification, Commercial Flight Standards, in Ottawa, by telephone at 613-993-4692, or by e-mail at firstname.lastname@example.org.
Original signed by
- Footnote 1
- Footnote 2
- Footnote 3
- Footnote 4
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.