PPRuNe Forums - View Single Post - B727 undershoot accident at Pohnpei, Micronesia in 2008
Old 10th July 2013 | 20:34
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JammedStab
 
Joined: Apr 2008
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Does your 737 have the Hydro-Aire Mark III anti-skid system which seems to be what many if not all 727's have installed?

If so, then "each tire has a wheel speed transducer, a little generator that produces power proportional to the speed of the tire. This goes to a control shield which interprets this signal as wheel speed. It is then compared to another tire. If the signal degrades (speed drops) on any given tire in comparison to its reference tire, an electrically operated hydraulic control valve limits the amount of hydraulic pressure available to the brake for the tire that is skidding. If the skid goes into a full scale locked wheel situation, pressure can be completely cut off. Then, as the wheel speed of the skidding or locked wheel approaches the speed of the reference wheel, pressure is slowly reapplied. The whole process should take about 20 seconds."


By the way, Boeing invented the anti-skid system and then licensed it to brake vendors, ie Hydro-Aire.

Other aircraft such as the HS-748 and Caravelle had Dunlop Maxarets for protection. These were all-mechanical.
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