A93C0169-Controlled Flight into Terrain-Athabaska Airways Limited-Sandy Bay, Saskatchewan-12 October 1993
Safety Action Taken(as presented in the TSB Report)
Accidents Involving Controlled Flight into Terrain
This occurrence is classified as a Controlled Flight into Terrain (CFIT) accident. CFIT occurrences are those in which an aircraft, under the control of the crew, is flown into terrain (or water) with no prior awareness on the part of the crew of the impending disaster. The Board notes with concern that, over the 11-year period from 01 January 1984 to 31 December 1994, 68 commercially operated aircraft (not including those conducting low-level special operations) were involved in CFIT accidents. In view of the frequency and severity of such accidents, the Board is conducting a study of CFIT accidents to identify related systemic deficiencies. The study includes, inter alia, an examination of CFIT data on VFR operations at night and on contributing factors such as somatogravic illusions.
Safety Action Required
(as presented in the TSB Report)
Pilot Licence Restrictions - Practical Flight Tests
The pilot's vision had been considered by an Aviation Medical Review Board (AMRB). Following a practical flight test, the pilot had been issued a commercial licence in accordance with medical standards allowing the option of flexibility for vision; his licence indicated that he was required to wear prescription bifocal glasses while flying. The practical flight test had been conducted during daylight hours in visual meteorological conditions (VMC); the pilot's duties at the time of the occurrence required that he fly at night and in instrument meteorological conditions (IMC). The flight test environment was not typical of the most difficult conditions in which the pilot was expected to fly.
In the spring of 1990, the TSB investigated another occurrence in which the validity of an AMRB-requested practical flight test was also brought into question (TSB A90Q0090). In this accident, the TSB determined that, because the pilot had only limited use of his right leg, he was unable to recover from a spin in the ultralight he was flying. The flight test was conducted in a category of aircraft different from that which the pilot was licensed to fly, and the in-flight exercises apparently did not include manoeuvres which typically would have placed the greatest demands on the pilot's right leg.
Neither the content of the flight tests nor the environment in which they were conducted was representative of the challenges that these pilots might encounter while exercising the privileges of their respective licences; nor had the pilots' actual licences been annotated to indicate limitations to any operational aspects of flying associated with their category of licence.
The Board accepts the principle of issuing licences with a flexibility for various medical conditions. It is also recognized that it may be impractical on AMRB flight tests to cover all aspects of the flying environment. However, based on these two occurrences, there appear to be inconsistencies between the flying abilities actually being verified on the flight tests and the follow-on restrictions being placed on licence privileges. Consequently, pilots with licences issued under the medical flexibility option may be flying in aircraft or environments beyond their demonstrated abilities. In this occurrence, fare-paying passengers were relying on a pilot to safely fly in conditions in which his vision may have hampered his ability to maintain adequate visual reference with the ground and avoid obstacles.
To reduce the likelihood of other pilots with licences issued under the medical flexibility option inadvertently operating aircraft in conditions beyond their demonstrated ability, the Board recommends that:
The Department of Transport review all pilot licences issued under the medical flexibility option to ensure compatibility of verif ied pilot abilities and licence privileges. (A95-13)
Transport Canada's Response:
Transport Canada Aviation (TCA) share the Board’s concern that a practical flight test should verify a pilot’s ability under the conditions in which he/she will be flying. As the Board pointed out "... it may be impractical on AMRB flight tests to cover all aspects of the flying environment"; however, TCA agrees that the applicant should be tested under conditions representative of the most difficult conditions in which he/she will be expected to fly.
The question of how a practical flight test under flexibility should be carried out is a subject which is under constant review. The vision standards under flexibility were addressed at the Visual Standards conference in June 1990 and again at the Visual Standards Conference in May 1995. In addition the subject is reviewed whenever there is any new information or new grounds for challenging the existing standard. For example applications for Licence Validation Certificates where the applicant does not meet the medical standard have also been made on the grounds of Human Rights. These applications provide another trigger for review and refinement of the standards and procedures of TCA for issuing Licence Validation Certificates under the "flexibility" provisions.
As a result of the Board’s recommendation, TCA will review the practical flight test procedures for future tests with the view of ensuring that the abilities being tested and the privileges being granted are compatible.
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