DASH 7 DAZE Oct/Nov 2009 AMU Magazine

DASH 7 DAZE by Sam Longo AME A&P

The all white Dash 7 floated across my field of vision, its four “rubber-band quiet” engines and props churning the air as it climbed in a graceful arcing south turn out of Toronto’s Island Airport. It was a treat to see one again, immediately transporting my mind back to my early days with DeHavilland back in 1977.

I was picking up my wife Irene at our usual meeting spot near her work on Queens Quay at the base of Bay Street in downtown Toronto recently, when this white vision appeared. Being very close to Toronto’s City Center Airport, it is a common sight to see various aircraft types winging skyward for destinations unknown. However it was a rare sight to see this white Dash 7 emblazoned with large black letters spelling out UNITED NATIONS doing repeated circuits for my personal viewing pleasure.

The Dash 7 has always been one of my favorite aircraft. As a young airframe mechanic working for DeHavilland I worked on the “Sevens” assembly line in the very early days of its production, having a hand in the construction of the first three production aircraft. Later in my career at DH I also helped de-bug these magnificent aircraft as they worked their way through Test Flight. I recall one particular job quite clearly while on the production line. A line foreman called me over to join a group of engineers gathered around a large blueprint near the back of the fuselage. As is often the case with early production the aircraft construction was ahead of the latest structural revision drawings. The rear emergency hatch opening was built up with six skin-doublers when the new revision called for seven. The foreman explained to me that I had to carefully drill out the hundreds of rivets, insert the new doubler, and re-rivet it all with an absolute minimum of oversized rivets. In addition each layer was sealed with PRC compound, which had to be scraped clean, re-sprayed with zinc chromate and re-sealed. This tedious job took me almost three full shifts to complete. Ironically (no pun intended), as I found out later, the entire aircraft was never to fly but instead was installed in the “Iron Bird” a giant hydraulic test rig used for destructive fatigue testing!

Another memory from my test flight time concerned some of the early sealing problems with the passenger entry door. Seeing as it was DeHavillands first pressurized aircraft it was not surprising to have a few leakage snags to sort out. As I recall the, then innovative, pressurized door seal was particularly troublesome. They must have eventually worked it out considering the newer Dash 8 used a similar design that was relatively trouble free.

The Dash 7 was the result of extensive market research that showed the potential success of using “super quiet” STOL turboprops flying out of inner city airports and short stub runways. Pratt and Whitney Canada worked hand in hand with DH to produce the PT6-50 engines utilizing state of the art Hamilton Standard four bladed props. The combination was a great success giving the aircraft world-class performance with minimum noise. Unfortunately the plan was just a little ahead of its time. Despite niche markets sales such as Rocky Mountain Airways and Spantax Airlines of Spain the sales orders never quite met the companies full expectations. Lack of inner-city airport development, along with a trend toward twin-engine turboprops kept the final production numbers to a total of only 111 aircraft. Despite its excellent in service track record, the Dash 7 never realized the success that it deserved.

However on a more positive note, much of its engineering technology paved the way for its successor, the twin engine Dash 8 which has evolved into the excellent, class leading, Bombardier Q-400 series of aircraft. I recently had the pleasure to fly out of Toronto’s City Center airport on one of Porters Q-400’s bound for Halifax, and found the entire experience very enjoyable. Their excellent service and on time scheduling made the grief of large airports like Pearson a distant memory. As we took off I noticed that same white Dash 7 sitting on the tarmac, and immediately realized that DH had the right idea over 30 years ago. I was now flying within the current reality, taking off from a city center airport and in my humble opinion that “old idea” appears to work very well.

As for the white Dash 7, it was wonderful to see that it was also still working well doing humanitarian service for the United Nations in other countries. Success is measured in many ways, but a great aircraft doing great work should always make us proud. The DeHavilland Dash 7 continues to earn it keep around the world, a quiet reminder to all nations that Canadians have a rich history building truly superb aircraft.

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