ALF5071H said (Overtalk comments interspersed in
blue)
OVERTALK Having been involved with a few military and civilian aircraft trials relating to aerodynamic (nose up/back stick) landings, the answer to your proposition remains as given in the other threads; it is to follow the manufacturers procedures. Hasn't anything whatsoever to do with aerodynamic braking (note spelling of "braking"). In fact it's quite silly to attempt to equate aerodynamic braking with what's being suggested. What's being advocated is a progressive and tempered introduction of backstick once nosewheel is on, spoilers are deployed, reverse is selected and braking has commenced. Note that all three of those traditional retardation measures cause a strong nose down pitching moment. Trying to pretend otherwise is very "imaginative" - unless your a/c sports a tailwheel...... so the nose will NOT rise. Even without those three cumulative nose-down pitching moments, a normal CofG distribution will accord a nose-down moment.
Do pilots really think that they have discovered something new in aerodynamic breaking[sic] which manufacturers have not considered? If there were better techniques, then we would all be using them in our over competitive industry. The core of many manufacturers’ advice is to concentrate on the important and most effective means of stopping the aircraft, particularly by using maximum braking with all wheels firmly on the ground.The advocated technique is merely a means of very quickly getting maximum weight upon wheels (or as you say, all wheels firmly on the ground - aka traction). This minimizes the intervention of anti-skid, which makes braking less effective the more it has to cut in to maintain wheel rotation. Remember that it's stopping the wheel that blows the tyre. Two ways of NOT stopping the wheel = antiskid (decreases braking effectiveness) and utilizing UP elevator to push the maingear into the pavement. Just because the aircraft is on the ground does not mean that the controls are ineffective and will not change the load distribution, you can lift the nose in many aircraft types even against brakes and reverse. The HS 125 for example can be steered on the runway with aileron even though full lift dump is deployed.
Some naval aircraft, which for obvious reasons may not have had the best brakes, were allowed to use aerodynamic braking for land based operations. However, there were many pilots who misjudged the runway length such that when the nose was lowered / effective braking applied, insufficient runway remained. These pilots would have been better placed to use full brake, even with the risks of brake fade or overheating, which would have required a tow off the runway; that situation would have been better than a tow out of the mud. Some very muddy and irrelevant thinking here. Best to stick with aerodynamics rather than anecdotal bombast and bluster...
Similarly, my limited trials experience in landing on snow confirmed that the ‘keep it simple / back to basics’ advice for stopping was the most effective. Get the aircraft on the ground, right place, and right speed, lower the nose, and use max brake.Couldn't agree more. However most overruns are caused by pilots making human errors, perhaps due to illusion, perhaps fatigue, possibly indecision. The recommended "introduced backstick" technique may have made all the difference at Toronto and Midway. I reiterate that it is merely a very effective method of adding main-wheel traction on contaminated runways for increased braking effectiveness - and one that has been widely overlooked and apparently, is only being used by a competent few. When you are surrounded by variables and indeterminants such as unreliable and optimistic braking action reports, downdrafts, skittish tailwinds and mu-meter readings, it is always nice to have a big trick up your sleeve. Those that don't will always be the ones that make the headlines and have to go find another career. Blindly believing that the manufacturer knows all and tells all is for blind men. The aircraft would stop ‘when it was going to stop’. The ground roll landing distances were measured very accurately in the fresh snow.
For trials reasons the conditions were at the limit or in excess of any runway condition approved commercial operations; be assured that neither I nor anyone else has need of any more experience of sliding uncontrollable down the runway hoping that it was long enough. Furthermore, if the cross wind had exceeded 5 kts I doubt that the aircraft would have remained on the runway, as both rudder and steering were ineffective.