Ed Cesnalis Posted May 6, 2013 Report Share Posted May 6, 2013 Ok we know the mantra by now, 62kts over the threshold, no touchdown speed given but plenty of warnings about damage due to slow speeds, no need to stall or come close, fly it on. I don't see how we can have this argument ( land near stall speed vs fly it on ) without considering that Mr. and Mrs. Bigs are located at Carson City, elevation 4,705'. A rule of thumb is helpful in determining actual ground speeds. TAS= [(IAS x 2%) • (ALT/1000)] + IAS Assumptions: Bigs is flying it on at 60kts; DA=7,000' ; Winds variable bigs always claims that it is easier on your gear if you land faster and this statement of course is counter to laws of physics. Speed at contact indicates quantity of kinetic energy ( bigs is actually warning about high vertical speeds. ) Simply arguing a high vs low approach or landing speed does not address the vertical speed. I assume the pilot is controlling vertical speed to avoid damage from that cause. Lets see what happens to that speed on a summer day where bigs will do his typical landings. TS [TouchdownSpeed] = 60 x .02 x 7,000 / 1000 + 60 = 68.4kts So we are approaching 70kts at contact, that's getting up there, hope we have the 'tundra' gear. Carson City is high desert, with high terrain in the lee of the Sierra Nevada, this means a fair amount of turbulent conditions and variable winds. Lets throw in something that happened to me 2 days ago here in Mammoth. I was flying left traffic for Runway 9 and the winds switched 180 degrees when I was on downwind for my 2nd landing. It was first obvious to me by the high ground speed on final but I did the downwind landing anyway for practice. So lets throw in a 13kt tailwind component, saying that bigs is trying a downwind 'fly it on' or maybe he just missed the clues and is doing the downwind landing without realizing it. TS = 60 x .02 x 7,000 / 1000 + 60 + 13 = 81.4kts Carson City is proximate to a number of airports at higher elevations yet, up to Mammoth at 7,100' and there are landing opportunities up to 11,000' on things like dry lake beds, abandoned military strips and high altitude roads. The speed = safety mentality can bite extra hard up here. Link to comment Share on other sites More sharing options...
This topic is now archived and is closed to further replies.