The History of Flight Inspection in Canada

Brief History

Since the beginning of aviation in Canada, the Department of Transport was responsible for establishing and maintaining all airway and airport facilities throughout the country. As the volume of air traffic steadily increased, radio aids were introduced to facilitate bad-weather air navigation. To give maximum benefit to the use of Canadian airspace, the radio aids had to be reliable and accurate. It was recognized early on that signals received in the air were not always consistent with ground measurements. It became necessary to carry out flights to verify the accuracy of the signals radiated by the ground based radio aids. This was the beginning of flight inspection in Canada. The Department of Transport took on the new responsibility of acquiring and outfitting aircraft to do the flight inspection task.

Official flight inspection in Canada began in the late 1940's using the Beechcraft D18S aircraft. The fleet eventually grew to ten aircraft, which were tasked with the flight testing of the Low Frequency Radio Ranges, Cone of Silence Markers and Instrument Landing Systems. The country was divided into six regions. Depending on its size, each region was allotted one or two aircraft and the responsibility for the flight inspection of its radio aids.

The avionics equipment list for the Beechcraft D18S aircraft included the following items:

Esterline-Angus oscillographic recorder and DC amplifier;
MN-85FA VOR/LOC receiver;
51V2 glide path receiver;
MN53B marker receiver;
DTR360 VHF transceiver;
BC453 LF range receiver;
ARC21 ADF receiver;

The Esterline-Angus recorder was spring wound and used a four-volt DC source to activate a timing pen. Only one parameter was recorded, usually the crosspointer-deviation signal. The recording was in red ink plotted on six-inch wide paper.

The Beech18 aircraft were later complemented with five DC-3 aircraft to flight inspect VOR, TACAN and ILS. They were also used for flight checks of secondary radar. The DC-3 brought with it greater capabilities along with more working space for the crews. The recorder used on this aircraft was capable of displaying multiple parameters, which made it possible to simultaneously evaluate both VOR and TACAN signals.

In 1965, The Beech King Air A90 was added to the fleet. This brought the total complement of aircraft to ten Beechcraft D18S, five MacDonald Douglas DC-3 and six Beechcraft A90 King Air. Shortly afterward, the Beechcraft D18S aircraft were de-commissioned having been replaced by the A90. The A90, equipped with an UNACE (Universal Aircraft Calibration Equipment) console, provided the same flight inspection capabilities as the DC-3.

In 1974, the DC-3 aircraft were replaced by a fleet of 12 Beechcraft A100, 2 aircraft per region.

In 1978 a Grumman Gulf Stream II was purchased and operated out of the Transport Canada headquarters in Ottawa. The main role of this aircraft was to perform flight inspection of NAVAIDS above the 60th parallel.

Today this technology has given way to Differential Global Positioning System (DGPS) as the truth system of the future.

During the period from 1980 to 1985 a major study was undertaken to re-structure the flight inspection organization in Canada. This was triggered in part because of the crash of one of the King Air flight inspection aircraft (CF-CAS) in 1979 killing two pilots. The study concluded that the present fleet of King Air aircraft was not suitable for the flight inspection role because of the airframe stresses encountered in the low level-flying environment. The higher than normal level of turbulence contributed to the premature aging of critical wing components, which went undetected. The study team also concluded that the flight inspection program could be run more efficiently from one centralized base in Ottawa using long range, high performance aircraft. As a result of this investigation, the six regional operations were consolidated into a single base located in Ottawa. Four aircraft, two CL 601 3A Challengers and two De-Haviland Dash-8 aircraft, were purchased to replace the King Air fleet. The new aircraft were equipped with a computerized Digital Flight Inspection System (DFIS), which was designed and manufactured by the Transport Canada flight inspection engineering group.

In early 1985 these four aircraft began taking over the regional flight inspection workload. The transition was completed in 1986. Improvements in flight inspection methodology led to greater efficiencies and the eventual removal from the fleet of one DASH-8. The flight inspection program continues today with two Challengers and one DASH-8.

Throughout the history of flight inspection in Canada, optical tracking of the aircraft using a theodolite was the primary truth system. In the mid-eighties, with the introduction of the centralized fleet, SCAPE (Self Contained Aircraft Positioning Equipment) was used as an alternative truth system. This system relied upon the use of an INS. The position updates obtained from surveyed lights located at the runway thresholds, provided near real-time aircraft position at the threshold with an accuracy of 2 to 4 inches.

The Present

NAV CANADA has established a national flight inspection and calibration program that is in conformance with the recommendations specified by the International Civil Aviation Organization (ICAO), and encompasses all public, military and private facilities that support the Canadian Air Navigation System. Specific NAV CANADA publications detail the procedures, tolerances and inspection cycles for each type of facility.

The flight inspection systems currently installed in the NAV CANADA aircraft were designed and built by the Flight Inspection Engineering group (starting in the late 1970s). They are capable of examining all types of navigation aids, displaying the results on a computer screen and generating written reports. The flight inspection system is modular and can readily accommodate additional sensors or test equipment to facilitate special flight tests or evaluation programs of new navigation system concepts or sub-components. Software design permits "in- house" changes to existing procedures or development of totally new programs to support new requirements. This capability has enabled extensive SatNav testing and will contribute to the transition from a conventional to a space-based Air Navigation System.

The following is a table of the NAVAIDS and the flight inspection periodicity of the various ground-based systems installed in Canada:

To date approximately 100 GPS/NPA have been commissioned.

The NAV CANADA Flight Inspection Organization (NCFIO) has implemented a NAVAID performance based flight inspection program. The extended flight inspection interval is applied to facilities with a stable performance history.

In 1999 the Canadian flight inspection program required a total of 1725 flight hours (en-route and on-site) to complete.

The NCFIO is unique because of the requirements imposed by Canada's large landmass, a scattered population, and environmental extremes.

The flight inspection officers (technologists) have an extensive background in NAVAID maintenance and repair, permitting them to assist ground staff in troubleshooting and correcting detected problems. This reduces out-of-service time of critical or remote NAVAIDS and prevents a costly return flight.

The flight inspectors (pilots) have extensive and varied experience and a comprehensive knowledge of approach procedure design and airspace requirements; this allows for objective evaluations of the efficiency and flyability of published procedures, thereby ensuring that user demands are safely met.

The aircraft used in the flight inspection role meet requirements with their appropriate blend of medium and long range capabilities and high transit speeds. They provide a reasonable working environment for the extended periods crews must stay airborne (4-6 hours) and are large enough to carry all the equipment demanded by the flight inspection task. These aircraft are manufactured to transport category standards, which ensures their usefulness for the full extent of their designed airframe "life" and provides a safety buffer through redundancy of systems.