TP 13579 PROCEEDINGS of the 2nd International Meeting ... - UQAC

IMAPCR ’99
19. Mr. Croll presented several overheads showing correlation between aircraft µ braking versus
ground speed; the Falcon 20 µ braking versus CRFI; slip ratios; and directional control
problems on low friction surfaces. He presented a video that elaborated on the test program.
It also showed instances where snow was ingested into the engines, causing a flameout, and
two recorded cases of aircraft lateral departure from the test section.
20. Conclusions of these tests indicated no consistent variation of aircraft braking coefficients
with ground speed. A good correlation existed between the Falcon 20 and the CRFI on
uniformly contaminated surfaces. Increase in wheel slip ratios with decreasing ground speed
was noted. Reduction in directional control at lower speeds on ice-covered surfaces was also
recorded. Mr. Croll recommended that additional testing should be done using different
aircraft and runway conditions, including slush and chemicals. Other testing on the Falcon
20 should include contaminant drag and crosswind effect.
21. Questions were raised about using different braking coefficient measures in testing (Falcon
tests versus the NASA tests). Mr. Croll replied that a need exists to standardize the
coefficient given to the pilot. In response to other questions, Mr. Croll explained that tests
were not done on damp or wet runway conditions; the antilock braking system (ABS) was
disabled on the test runs and thrust reversers were not used.
Dash 8 Aircraft Performance Testing on Contaminated Runway
Surfaces
22. Edward Lim, Chief of Performance at Bombardier Aerospace, de Havilland division,
Canada, presented the results of testing done in February 1998 at North Bay. The test
sequence was:
• ground vehicle tests;
• RTO and landing tests;
• ground vehicle re-tests.
23. The objective was to determine contaminant drag and aircraft braking coefficients for the
Dash 8 under three contaminant types: rough ice, moderately smooth ice, and sand on
moderately smooth ice.
24. Test results indicated no appreciable impingement or displacement drag on the three surface
types. Second, brake friction coefficient (as a percentage of dry) was established for all three
surface types.
25. In response to questions on the test, Mr. Lim pointed out that a triple axis accelerometer was
used. The outside temperature was -10°C, and there was no evidence of the aircraft breaking
through the ice surface.
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