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Assessment of the response to TSB recommendation A20-02

 Recommendation A20-02 in PDF [281 KB]

Landing minima in Canada


On 26 February 2018, a Beechcraft King Air A100 (registration C-GJXF, serial number B‑159) operated by Strait Air (2000) Ltd. was conducting charter flight NUK107 under instrument flight rules, from the Sept-Îles Airport, Quebec, to the Havre St-Pierre Airport, Quebec, with 2 crew members and 6 passengers on board. The aircraft conducted an approach to Runway 08, which was snow-covered, while visibility was reduced due to heavy snow showers, and landed approximately 3800 feet beyond the threshold, at approximately 700 feet from the end of the runway. It continued its landing roll beyond the runway until it came to rest in a snowbank, approximately 220 feet beyond the end of the runway. The accident occurred in daylight, at 1120 Eastern Standard Time. The emergency locator transmitter, transmitting on 406 MHz, did not activate following the occurrence. The aircraft sustained substantial damage. Four of the occupants received minor injuries.

The Board concluded its investigation and released report A18Q0030 on 21 May 2020.

TSB Recommendation A20-02 (May 2020)

In designing instrument approaches, the published minimum visibility represents the minimum visibility at which a pilot on approach at the decision height (DH) or the minimum descent altitude (MDA) should be able to establish and maintain the visual reference required up until landing.

International Civil Aviation Organization (ICAO)Footnote 1 standards and recommended practices stipulate that an instrument approach shall not be continued unless the reported visibility is at or above the specified minima. These minima are published on approach charts based on the approach type and lighting.

Various civil aviation authorities throughout the world (such as the U.S. Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA)) have established that the authorized visibility minima are those specified and published for the approach. Therefore, to determine whether an approach is authorized, it is simply a matter of comparing the reported visibility with the visibility published on the approach chart. Consequently, air traffic control (ATC) will not clear an aircraft for approach if the reported visibility is less than what is published on the approach chart.

In Canada, visibilities published on approach charts are provided for information purposes only.

To determine whether an aircraft can legally land at an aerodrome in Canada, consideration must first be given to the operational restrictions that apply to the aerodrome in question to ensure that the aerodrome is suitable for the manoeuvre being executed.Footnote 2 One of the determining factors is the aerodrome’s operating visibility, which is defined in the Canada Air Pilot (CAP 5) in the general pages pertaining to operating minima.Footnote 3 This operating visibility limit is published in the Canada Flight Supplement (CFS), specifically in the box reserved for runway information. If an aerodrome’s operating visibility limit is not published in the CFS, it means that operations are not authorized when visibility is less than ½ statute mile (SM).

Next, the minimum visibility for an approach ban must be calculated to determine whether the approach can continue to the DH or the MDA. This minimum visibility is calculated based on the visibility published on the approach chart, and varies depending on the type of operations:

According to this calculation, the minimum visibility for an approach ban in Canada is less than the visibility published on the approach chart in every case. Consequently, it is likely that, once at the DH or MDA, pilots are not able to establish the required visual reference that will help them make a safe landing.

Between December 2006Footnote 4 and December 2019, 31 incidents occurred following approaches conducted below the MDA with few visual references. Of these 31 incidents, 17 occurred during a landing in weather conditions where visibility was below what is published on the approach chart.Footnote 5 Furthermore, this situation continues to occur today: 9 of the 17 incidents have occurred within the past 5 years.

In Canada, due to the complexity and variations in minima based on the type of operations, it is difficult for ATC to determine whether the planned approach is banned. It will clear an aircraft for approach regardless of the published minima, contrary to what is done elsewhere in the world. Therefore, it is up to the captain to interpret the approach ban, and it is the captain who decides whether or not to continue with the approach.

In this occurrence, the approach ban in effect in Canada did not prevent the captain from continuing with the approach in weather conditions that were one third of the authorized visibility minima and one quarter of the visibility published on the approach chart. During the approach, when the aircraft arrived at the MDA, it was up to the pilot alone to determine whether or not he had established the visual reference required to continue the descent and landing. Therefore, it is reasonable to conclude that the approach ban was ineffective in stopping this approach while visibility on the ground was below the minimum required for an approach ban, which contributed to the runway overrun.

As this occurrence demonstrates, if there is no mechanism to stop an approach that is in fact banned, then pilots may choose to continue their approach, which increases the risk of an approach-and-landing accident.

Consequently, the Board recommended that

the Department of Transport introduce a mechanism to stop approaches and landings that are actually banned.
TSB Recommendation A20-02

Transport Canada’s response to Recommendation A20-02 (August 2020)

The two recommendations are related and will be addressed in a single response.  

TC agrees with Recommendation A20-01 and, as outlined below, has already initiated work to implement improvements to the regulations governing approaches and landings at Canadian aerodromes.  

TC also agrees with Recommendation A20-02. While recognizing that it may be difficult to stop all approaches and landings that are prohibited through the regulations, introducing simpler regulations in keeping with Recommendation A20-01 will make them easier to follow and to enforce. Furthermore, TC will investigate possible improvements to education and enforcement as part of its upcoming work in this area.

The safety issues raised by the two recommendations are not unknown to TC. The complexity of the current approach ban regulations, promulgated in 2006, are the result of multiple compromises following consultations with industry to reflect the diverse realities facing Air Operators. As such, TC has already carried out significant work on this issue in the past five years:

Due to the complexity of the issue, stakeholders raised specific concerns related to the workload associated with implementation; potential service impacts in the North if changes to the approach ban are not done alongside infrastructure improvements; applicability of the changes to the approach ban to helicopter operations; and the need to harmonize proposed changes to the approach ban with changes to lighting standards.

Due to other competing priorities, this was the most recent work carried out by TC on this issue.

TC recognizes that more work needs to be done to mitigate the risks. To this end, revisions to the approach ban regulations (A20-01) must precede steps to ensure the new regulations are followed (A20-02). Building on the aforementioned work and comments received from stakeholders, TC is forming, and will lead, an industry working group on this issue.  The working group will have the mandate to deliver on the following:

In order to produce the deliverables above, the work will be divided into two phases:

TSB assessment of Transport Canada’s response to Recommendation A20-02 (November 2020)

In its response, Transport Canada (TC) indicated that it agrees with Recommendation A20-02 and recognizes that introducing simpler regulations governing approaches and landings at Canadian aerodromes will make the regulations easier to follow and to enforce.

To that end, TC will lead an industry working group that will draft a Notice of Proposed Amendment to update approach ban regulations, as well as the supporting documentation and guidance. TC expects to publish the proposed regulations in the Canada Gazette, Part I, by the end of 2021.

This working group will also review various methods available to encourage and enforce compliance with the updated approach ban regulations.

The Board is encouraged by TC’s planned actions to address the safety issues associated with the complexity of the landing minima in Canada. These actions, when fully implemented, have the potential to substantially mitigate the risks associated with the safety deficiency identified in Recommendation A20-02.

Therefore, the Board considers the response to Recommendation A20-02 to show Satisfactory Intent.

Next TSB action

The TSB will monitor the progress of TC's planned actions to mitigate the risks associated with the safety deficiency identified in Recommendation A20-02, and will reassess the deficiency on an annual basis or when otherwise warranted.

This deficiency file is Active.