Guy Norris/LOS ANGELES
NORTHWEST AIRLINES has begun operational tests of an experimental broad-area wing-contamination detection system on a McDonnell Douglas (MDC) MD-82.
The test is aimed at the eventual development and certification of a production-standard system which will provide crews with automated, real-time, aircraft surface-contamination information. If successful, it will replace manual ice-inspection and possibly serve as the primary means of ice detection.
The system, made by Minnesota-based Rosemount Aerospace, detects the presence of ice, sleet, snow, freezing rain and de-icing fluid by measuring the effect of the contaminant on an ultrasonic wave passing through the surface of the wing.
A production variant of the system, called the HALO, will be able to distinguish between the various types of contaminants, and so indicate how much lift the wing will be able to generate.
A Rosemount-led team involving MDC's Douglas Aircraft division, Northwest and a company affiliated to State College, Pennsylvania, called FBS, developed the system after winning a $2.4 million contract from the US Advanced Research Projects Agency in February 1994. Tests on the MD-82 will end in May.
The experimental system consists of an aluminium plate located above the "cold corner" of the inboard fuel tank on the left wing. This is a notorious area of ice formation on MD-80s, and anti-icing/de-icing systems are being developed to combat the problem.
A single transducer and receiver are located on the test plate, although a production version could contain several multi-role transceivers to form a network for coverage of a much larger area.
The sensors on a large-scale production system could be located beneath the upper-wing skin, rather than on top of it.
A prototype production system is expected to be built in the third quarter of this year and certification is due in mid-1996.
Two more airlines, Toronto-based Canair and the new Midway Airlines, are helping AlliedSignal Aerospace Canada with "further development" of its Clean Wing Detection System (CWDS). The CWDS can be used to detect and classify surface contaminants using electro-thermal sensors and was developed with Instrumar. As well as being tested on a Canairs Boeing 737 and Midway Fokker 100, the CWDS is also being flown on an Air Atlantic British Aerospace BAe 146-200.
Source: Flight International
