de Havilland Canada Dash 7

Source: Wikipedia, the free encyclopedia.
"Dash-7" redirects here. For other uses, see Dash 7 (disambiguation).

Dash 7
Brymon Airways Dash 7 in 1983
Role STOL regional airliner
National origin Canada
Manufacturer de Havilland Canada
First flight March 27, 1975
Introduction February 3, 1978
Status In service
Primary users Various airlines
Venezuelan Navy
Produced 1975–1988
Number built 113
Developed into De Havilland Canada Dash 8

The de Havilland Canada DHC-7, popularly known as the Dash 7, is a

Bombardier. In 2006 Bombardier sold the type certificate for the aircraft design to Victoria-based manufacturer Viking Air
.

Design and development

In the 1960s, de Havilland Canada was already well known worldwide for their series of high-performance STOL aircraft, notably the very popular

Hawker Siddeley 748
.

The de Havilland Canada company personnel felt they could compete with these designs in a roundabout way. With their excellent STOL performance, their designs could fly into smaller airports located in city centres and smaller, outlying, more austere airports having runways that the other aircraft could not easily use (unpaved, unimproved). The original specification called for an aircraft that could carry 40 passengers[1] and operating from runways only 2,000 ft long (610 m),[1][2] and designed for, with a full load of passengers, the ability to fly 700 nautical miles (1296km),[2] or a range of 805 statute miles. [Note 1]

With new noise restrictions coming into effect throughout the 1970s, [2] an aircraft tailored for this role would also have to be very quiet. Propeller noise is a factor of blade length and chord and the speed at which it rotates. To meet these new regulations, the new design used much larger (oversized) propellers geared to rotate at a lower speed than is normally designed. Much of the problem sound from a typical propeller is generated at the tips of the blades which are rotating at or just beneath the speed of sound. By using oversize propeller blades, there is no need to have the blade tip reaching near the speed of sound, and the rotating speed can therefore be reduced without sacrificing thrust. In reducing the speed, this noise is reduced substantially. The Dash 7 often landed at only 900 rpm, and took off at only 1,210 rpm.

Dash 7 flight deck

In other respects, the new DHC-7 was essentially a larger, four-engine version of the Twin Otter: the general layout remained similar, with a high

aspect ratio, high-mounted wing, and similar details of the cockpit and nose profile. Changes included the addition of cabin pressurization (requiring a switch to a fuselage with a circular cross-section), landing gear that folded forward into the inner engine nacelles, and a large T-tail intended to keep the elevator clear of the propwash during take-off (the Twin Otter's empennage was a cruciform
arrangement).

The Twin Otter incorporated "

Fowler flap arrangement for high lift at low speed. During a typical STOL landing, flaps are selected to the 45° position, generating more lift and drag, thus allowing for steeper descents and lower approach speeds. Depending on weight, the VREF speed with flaps at 45° is between 70 and 85 knots. On touchdown, through "squat switches" in the main gear, the flaps automatically retract to the 25° position, thus reducing lift once on the runway and producing better braking performance. The flaps also retract to 25° when engine power is increased during a go-around procedure. The four-engine layout aids lift at low speeds due to the wide span of the propellers blowing air over the wing ("propwash"). When reverse thrust
is selected on landing, the props reverse pitch, push air forward, and slow the aircraft very effectively along with the antiskid main wheel brakes. More importantly, if an engine fails, the asymmetric thrust is much less than on a twin-engine layout, thereby increasing safety and allowing for a lower minimum control speed with an engine inoperative.

Operational history

Prototype DHC-7-100 at the 1978 Farnborough Air Show.
DHC-7 of London City Airways making its steep approach to London City Airport as another loads before departure to Amsterdam in 1988
Mojave Airport
in 2001

Development started in 1972 and the prototype first flew on March 27, 1975. Testing went smoothly, and the first delivery took place to

Telluride Airport located in the San Juan Mountains of southwest Colorado with this mountain airport having an airfield elevation of 9,078 feet thus making it one of the highest airports in the U.S.[4]

Kapalua Airport on the island of Maui, Hawaii was built by Hawaiian Airlines with a 3000-foot runway, specifically for Dash 7 operations. Scheduled passenger flights with new Dash 7 turboprops began on March 1, 1987. In 1993, this private airport was acquired by the state of Hawaii.

One hundred Dash 7 turboprops were delivered by 1984, when the production line was put on hold in favour of the

Dash 8. Another 13 were delivered between 1984 and 1988, when the production lines were removed when Boeing bought the company. The last Dash 7 was bought by Tyrolean Airways.[5]

The original Series 100 represents the vast majority of the aircraft delivered, and came in two models; the DHC-7-102 passenger version and -103 combi with an enlarged cargo door. These were followed by the Series 110 which met British CAA requirements, including the -110 and -111, and finally the Series 150 which included additional fuel capacity and an improved interior in the -150 and -151. Plans were made for a Series 200 with the new PT6A-50/7 engines which improved hot-and-high power, but these plans were shelved when Boeing ended production of the design.

The mixture of features on the Dash 7 met with limited commercial success. Most commuter airline turboprop operators used the aircraft as feeder liners into large airports, where the STOL performance was not considered important. In comparison to other feeder liners, the Dash 7's four engines required twice the maintenance of a twin-engine model, thereby driving up operational costs. Finally, those airports that did require a high-performance STOL operation were generally small and well served by the Twin Otters; had an airport needed a larger plane to serve its customer base, they would have built a longer runway. One exception to this was operations at

Embraer 190
types. Noise criteria remain strict in comparison with other international airports.

The Dash 7 also gained a number of military orders. The first of these was for two aircraft for the

Canadian Armed Forces, which needed them to transport high-ranking passengers and freight around Europe. These aircraft received the CF designation CC-132 and were delivered to 412 Transport Squadron at Canadian Forces Base Lahr, in West Germany.[6]

The United States Army operates several Dash 7 aircraft as surveillance platforms with the designation EO-5C (RC-7B before 2004)[7] under the Airborne Reconnaissance Low program.

Ottawa, Ontario
. During the summer, this aircraft conducts patrols throughout the Canadian Arctic, Alaska, and Greenland. During the fall and winter, this aircraft conducts patrols of the Great Lakes and east or west coasts of Canada as required.

The design of a much more "conventional" twin-engine design commenced at de Havilland in 1978, resulting in the extremely popular Dash 8. The DHC-7 production line eventually delivered 113, of which six have been lost and one scrapped. Many of the rest remain in service.[8]

The American band Wilco released a song called "Dash 7" on their 1995 album A.M.

Variants

Model 103 operated by Air Greenland with the forward cargo door open.
DHC-7-1
Prototypes, two built
DHC-7-100
Production passenger variant with a maximum of 54 passengers (with 43,000 lb or 20,000 kg takeoff weight)
DHC-7-101
Production passenger/cargo variant with a maximum 50 passengers and a left-hand forward cargo door (with 43,000 lb or 20,000 kg takeoff weight)
DHC-7-102
Production passenger variant with a maximum of 54 passengers (with 44,000 lb or 20,000 kg take-off weight)
DHC-7-103
Production passenger/cargo variant with a maximum of 50 passengers and a left-hand forward cargo door (with 44,020 lb or 19,970 kg take-off weight)
DHC-7-110
DHC-7-102 certified for use in the United Kingdom
DHC-7-111
DHC-7-103 certified for use in the United Kingdom
DHC-7-150
Improved 1978 version with higher gross weight, increased fuel capacity, and improved passenger amenities
DHC-7-150IR
One series 150 modified in 1986 for Transport Canada for ice/pollution patrols of the Canadian Arctic
CC-132
Canadian military designation for the Series 102/103
O-5A ARL-I (Airborne Reconnaissance Low – IMINT)
Converted by California Microwave Incorporated 1991–92
EO-5B ARL-C (Airborne Reconnaissance Low – COMINT)
United States military designation for Series 102
EO-5C ARL-M (Airborne Reconnaissance Low – Multi-sensor)
Converted by California Microwave Incorporated 1996
RC-7B ARL-M (Airborne Reconnaissance Low – Multi-sensor)
Redesignated EO-5C in 2004

Accidents and incidents

The de Havilland Canada DHC-7 has been involved in six accidents (and 10 incidents overall) with a total of 68 fatalities.[8]

Operators

Current airline and other operators

Arkia de Havilland Canada DHC-7 parked at Eilat Airport

As of July 2018, a total of 17 Dash 7 aircraft (all variants) remain in commercial service. Other aircraft remain in other services.[19][20]

 Canada
 Kenya
 United Kingdom
 United States

Former operators

 Argentina
 Australia
  • Jetcraft Aviation
 Austria
 Canada
 Colombia
 Denmark
 Greenland
 Guatemala
 Honduras
  • Sahsa
 Indonesia
  • Pelita Air Service
    (2)
 Israel
 Malaysia
 New Zealand
 Nigeria
 Norway
 Papua New Guinea
 Philippines
  • Asian Spirit
  • Zest Airways
    (Formerly Asian Spirit, now Air Asia Zest)
 Slovenia
 South Africa
 Tanzania
  • Regional Air Services (Tanzania)
 United Kingdom
 United States
 Venezuela
 South Yemen

Other civilian operators

The British Antarctic Survey (BAS) Dash 7 at Stanley on the Falkland Islands.

The

Punta Arenas, Chile, and the Rothera Research Station on Adelaide Island. It also operates to and from the ice runway at the Sky Blu Logistics Facility on the Antarctic mainland.[23]

Military operators

 Canada
  • Canadian Forces (two delivered 1979 to Canadian Air Mobility Tasking for use at CFB Lahr, flown until 1987 - replaced by DHC-8)[24]
 United States
 Venezuela
  • Venezuelan Navy
    (one delivered in 1982)

Specifications

Dash 7 undercarriage

Data from Jane's All The World's Aircraft 1982–83[25]

General characteristics

Performance

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

Notes

  1. ^ Obtained from the formula "sm = nm ·1.15". For comparision, the range is 795 miles for the 50-passenger DHC-Dash 7 (Srs 100) according to description found in website of BAE Systems [3]

References

Notes

  1. ^ a b Mark Finlay (3 February 2023). "The Story Of The De Havilland Canada Dash 7's Development & Entry Into Service". simpleflying.com. Retrieved 9 March 2024.
  2. ^ a b c Malcolm Ginsberg (21 May 2020). "De Havilland Canada Dash 7: STOL Airliner". Retrieved 9 March 2024.
  3. ^ "DHC-7 Dash 7". Retrieved 29 March 2024.
  4. ^ http://www.departedflights.com, Feb. 1, 1987 Continental Airlines system timetable
  5. ^ "Boeing de Havilland (Canada)". Flight Magazine. Flightglobal. 29 April 1989.
  6. ^ "de Havilland CC-132 Dash 7." Canada's Air Force, April 6, 2004. Retrieved: August 27, 2008.
  7. ^ "Non-Standard DOD Aircraft Designations." designation-systems.net. Retrieved: October 18, 2009.
  8. ^ a b "Aviation Safety Network Database: de Havilland Canada DHC-7." Aviation Safety Net. Retrieved: January 7, 2013.
  9. ^ "Accident Report 19820428-0." Aviation Safety Net. Retrieved: October 18, 2009.
  10. ^ "Accident Report 19820509-1." Aviation Safety Net. Retrieved: October 18, 2009.
  11. ^ "Accident Report 19820623-0." Aviation Safety Net. Retrieved: October 18, 2009.
  12. ^ "Accident Report 19830215-0." Aviation Safety Net. Retrieved: October 18, 2009.
  13. ^ "Accident Report 19880506-0." Aviation Safety Net. Retrieved: October 18, 2009.
  14. ^ "Accident Report 19981128-0." Aviation Safety Net. Retrieved: October 18, 2009.
  15. ^ "Accident Report 19990723-1." Aviation Safety Net. Retrieved: October 18, 2009.
  16. ^ "Accident Report 19990907-0." Aviation Safety Net. Retrieved: October 18, 2009.
  17. ^ "Accident Report 20020904-0 ." Aviation Safety Net. Retrieved: October 18, 2009.
  18. ^ "Accident Report 20060501-0." Aviation Safety Net. Retrieved: October 18, 2009.
  19. ^ "DHC-7 Record." CH-Aviation. Retrieved: April 27, 2012.
  20. ^ "World Airline Census 2018". Flightglobal.com. Retrieved 26 August 2018.
  21. ^ "DHC-7 Dash 7. De Haviiland Aircraft South Africa".
  22. ^ "DAL85intro".
  23. ^ "Aircraft Capability" British Antarctic Survey. 2023. Retrieved: 31 Mar 2023.
  24. ^ a b "Canadian Aerospace — Background — DeHavilland Canada Dash 7." Canadian American Strategic Review via "Archive", October 11, 2009. Retrieved: October 18, 2009.
  25. ^ Taylor 1982, pp. 29–30.
  26. ^ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
  27. ^ Dash 7 Approved Flight Manual
  28. ^ a b XdH Aviation Services

Bibliography

External links

Wikimedia Commons has media related to De Havilland Canada DHC-7.
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