In case anyone has not hear about the Tripartite Agreement, here once more are the words of Roger Tasse, author of the report on the Toronto Port Authority.  The Agreement is a contract that legally binds its parties, the federal government, the TPA and the City.  A section of the Agreement states quite clearly the noise restrictions on aircraft using the island airport.

Section 14 of the Agreement sets out quite unmistakably the upper noise limits.  It states plainly that the TPA shall not allow aircraft making excessive noise to operate out of the airport.  Excessive noise in the case of the category of plane that Q400 falls under is 84 EPNdB on take-off; 83.5 EPNdB from the sideline; 92 EPNdB on the approach.  EPNdB (Effective Perceived Noise Level in decibels) is a subjective noise level measurement commonly used in the aviation industry.

Both the International Civil Aviation Organization and the Q400 manufacturer, Bombardier, show that two the Q400 exceeds the Agreement’s limits in two of the three categories: sideline and approach.  The following chart illustrates where the Q400* goes off the rails.

                                         Take-off                     Sideline                     Approach
Tripartite Limits                   84.0                         83.5                             92.0
   
ICOA Data                             77.8                         84.0                             94.3

Bombardier Data                 78.0                         84.1                             94.9

The TPA’s consultant responded to the above information at the Noise Management Study Advisory Group with an explanation on a process on trading off higher limits with lower limits to justify the aircraft’s use of the airport.

Mentions of trade-offs bring to mind Transport Canada’s saga of the Q400 as a permitted STOL aircraft.

The Tripartite Agreement defines a STOL (Short Take Off and Landing) aircraft as
follows.

(j) “STOL aircraft” means any fixed wing aircraft other than jet powered aircraft capable of maintaining a 6 degree glide path on descent and a 6 degree climb profile on departure, and with electronic navigational equipment such as to permit approach and departure in accordance with specified air traffic control procedures. The capability of aircraft to meet the flight performance and navigation requirements will be certified by the Director-General, Civil Aeronautics.

When the City of Toronto questioned Transport Canada on the Q400’s ability to meet the Agreement’s definition of STOL, Transport Canada Deputy Minister Louis Ranger replied in a letter dated May 19, 2006 stated, “In closing, please be advised that, while it is Transport Canada’s position that the DHC-8 400 aircraft meets the definition of ‘STOL aircraft’ in the Tripartite Agreement, Transport Canada does not intend to issue any further certification in respect of this aircraft.” 

However, on January 25, 2007, then Minister of Transport Lawrence Cannon, Louis Ranger’s boss, in a response to a question by Olivia Chow, stated, ”Tripartite Agreement references to a six degree flight requirement only apply to Short Take-off and Landing Operations.  The Bombardier Q400 is not a Short Take-off and Landing aircraft.”

So, there we have it: two opinions on the Q400 as a STOL aircraft coming from the two top people in the federal ministry with the ultimate responsibility for the TPA.  Given the kind of leadership evident at the top, it will be interesting to learn the one or more interpretations on how the Q400 doesn’t violate the Agreement’s noise requirements, independent data notwithstanding.

In the meantime, the TPA insists that it is adhering to all its obligations under the Tripartite Agreement, including the use of STOL aircraft at the island airport.  It’s all a matter of trust. 

*Anyone familiar with Bombardier’s claim that Q stands for quiet may want to check out the company’s website, http://www.q400.com/q400/en/quiet.jsp for references to how quiet the aircraft is for people on the ground.  As the chart above shows, it isn’t.  The quiet is for those inside the plane, not outside.

Bob Kotyk