All air operators, flight operations personnel, airport and aerodrome operators and air navigation services providers
|File Classification No.:||Z 5000-35 U|
|Document No.:||CASA 2022-01|
The purpose of this Civil Aviation Safety Alert (CASA) is to advise air operators, foreign air operators, private operators, flight training units, pilots, flight dispatchers, aerodrome operators and Air Navigation Services Providers (ANSP) of a change in procedures for land and hold short operations (LAHSO).
The implementation of the global reporting format (GRF) for runway surface conditions has led both Transport Canada Civil Aviation (TCCA) and Canadian stakeholders to review various aspects of operations on wet and contaminant runways, including LAHSO. During our review of LAHSO procedures, it was observed that the Canadian requirements for LAHSO were at variance from those in the United States (US). Of specific concern was the fact that while the US Federal Aviation Administration (FAA) requires dry runways for LAHSO, here in Canada, LAHSO was conducted on wet runways and when contaminants were present on the runway (provided that the center 100 feet was either wet or dry).
The hazards and risks associated with aircraft operations on runways that are wet or contaminated with water, slush, snow, compacted snow, frost or ice – and the numerous accidents that have occurred during these conditions – are well-known and have been thoroughly documented. The importance of this safety issue is illustrated by the fact that runway overruns have been on the Transportation Safety Board (TSB) Watchlist since 2010.
Reporting wet conditions – especially in dynamic weather situations – is known to be problematic. Allowing LAHSO on wet runways can potentially compound this risk, as runway conditions can change from wet (less than 1/8 in or 3 mm of water) to standing water (greater than 1/8 in or 3 mm) very rapidly. The risks associated with operations on wet runways are documented in detail in:
- Appendix C of AC 700-057 – Global Reporting Format (GRF) for Runway Surface Conditions: Guidance for Flight Operations; and
- US FAA SAFO 19003 – Turbojet Braking Performance on Wet Runways.
Due to the dynamic nature of rainfall conditions, the timely and accurate reporting of conditions when water or moisture is present on the runway, is recognized to be challenging. Therefore, airport or aerodrome operators may not be able to report these conditions.
Allowing LAHSO on wet runways is also problematic because there are no regulatory requirements for pilots to revise dispatch landing distance calculations, or to conduct a time of arrival performance calculation. This could potentially pose the risk of an aircraft conducting LAHSO based on landing distance calculations that do not reflect conditions at time of arrival.
The allowance of contaminants on the runway, provided that the center 100 feet is either dry or wet, poses a potential problem for LAHSO where the aircraft manufacturer has recommended a nominal runway width that is greater than 100 feet. These aircraft include, but are not limited to, the Boeing 737, 747, 757, 767 and 777; as well as the Airbus A320, A330 and Airbus A380. In addition, this risk is compounded if any crosswind is present as the cleared width leaves no margin for any deviation from the runway centerline.
For LAHSO to be conducted in the US, the entire runway surface needs to be dry. The US requirements are listed in FAA order JO.7110.118A – Land and Hold Short Operations (LAHSO), which specifies that: for LAHSO to be conducted, the available landing distance (ALD) on the runway in use for the operation must be dry. These requirements are also outlined in TCCA AC 700-050 – Land and Hold Short Operations (LAHSO): Special Authorization and Guidance, which provides the conditions for Canadian operators to obtain the Special Authorization/Specific Approval (SA) which the US FAA considers a pre-requisite to conduct LAHSO in the US.
In order to mitigate the identified safety concerns, a decision has been made to harmonize Canadian LAHSO requirements with those in the US, where a dry runway (i.e., the entire runway surface is not wet and is free of contaminants) is required.
In consideration of the safety concerns identified above, the conduct of LAHSO will now be limited to dry runways only.
Accordingly, LAHSO operations are now prohibited:
- when a runway surface condition (RSC) NOTAM indicates that a runway is wet or has contamination present;
- when the weather report(s) indicates that precipitation is occurring; or
- anytime precipitation is observed by air traffic service (ATS) personnel or reported by an aircraft.
In addition, flight crews should not accept a LAHSO clearance if they are aware that the runway is not dry (wet conditions and standing water are not always reported).
Operators should review their company operations manuals and training programs to ensure that the above information is provided to flight operations personnel.
For related guidance, flight operations personnel are encouraged to review AC 700-057 – Global Reporting Format (GRF) for Runway Surface Conditions: Guidance for Flight Operations. In particular, the information in:
- Appendix C – Risks associated with wet conditions and standing water; and
- Appendix E – Landing performance assessments at time of arrival.
For more information concerning this issue, contact a Transport Canada Centre; or contact Commercial Flight Standards in Ottawa by e-mail at AARTFinfo-InfoAARTF@tc.gc.ca.
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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.