With airliners having a long fuselage their flare will naturally be a lot different than most GA aircraft, and in many ways, than corporate jets.
As the pilot eases the yoke of the airliner back into an increasing flare the nose will come up but also the main gear will increase the rate of descent to the runway in addition to the existing descent rate. if the pilot leaves it too late the act of increasing back pressure to arrest a higher descent rate will simply drive the main gear onto the runway at a higher rate than it would have been otherwise. Rotating around the c of g if you like. The result is a harder landing than the ego can stand. (Ask me how I know).
On the other hand if the pilot arrests the overall descent rate before the main gear's increased descent rate hits the runway they'll be rewarded with with the perfect touch down or, if done a little too high, by an extended float. This is followed by another harder than intended touchdown...unless the pilot can redo the flare and hasn't gotten too close to the runway.
Being able to repeatedly time the flare just right, in all weather conditions, is the result of experience, skill and cunning and blind luck. You can often tell when the pilot is in the blind luck phase when they pump the yoke in search of the runway which is tantalizingly close to the main gear.
A smooth arrival is nearly always the result of energy management during a stabilized approach which the pilot trains for and practices maybe several times each day.
I should add that touching down in the landing zone is highly encouraged by the airlines training pilots who demand touchdown in the right zone regardless of the pilots ego. The FAA also monitors those who float in search of the greaser and I know of cases where they contacted offenders. (not me).
Many modern airliners have main wheel trucks which dangle somewhat allowing the lower wheel pair to touch first starting the main wheel spin up sequence which in turn initiates several systems to work, such as ant-skid. Doesn't matter if the main wheels dangle forwards (767) or backwards (A330) and some trucks are flat but the rearmost wheels usually touch slightly beforehand.
Airliners with one set of main wheels per side (MD80, narrow body Airbus) seem to land quite well which may be just that they sit just right as the pilot flares. The 727-100 in this regard was the same, whilst the 727-200 series was not. The main gear sat further back. The -200 series would bite you just when you thought you'd make a nice smooth touchdown and most certainly would kick your butt if you flared too late or increased the flare because, as I mentioned above, the pilot then simply drives the main gear into the runway at a higher rate than he would have if he'd just let it be and taken the firm arrival (again, ask me how I know). MD80 guys always seem to do much better landings than 727 guys, unless the latter were in the -100s.
The secret to smoother landings in the -200 was if you could make yourself actually push the nose forward just as you were ready to touchdown. Rolling it on. Its counter intuitive and makes you feel you're going to wheel barrow, but it meant the nose was still in a flare attitude whilst the main gear 'rotated' around the center of gravity and as it rose opposite to the nose being pushed forward the main gears descent rate was reduced substantially and if done right would always reward the pilot. My first attempt on LGA's RWY 22 over the pier onto a damp runway worked perfectly. Capt asked how did I do that? Truthfully it was probably blind luck but I humbly accepted his praise.
Airliners with auto-land capability could annoyingly make the flare and touchdown process humiliatingly easy. Humiliating for the pilot that is. At 50' the auto-throttles retard and the aircraft flares and invariably touches down very nicely. Humiliating to have to inform a passenger that that great landing was performed by the airplane itself.
Equally humiliating to have to face the passenger after a 727-200 landing who says "was that a landing or were we shot down!".
By the way an airliner can and does go-around from as low as 50 feet above the runway in fact part of the CAT IIIA/B simulator training and recurrent includes a "go around from a very low altitude" and should the plane touch the runway during an auto land as the go-around is conducted its usually required to switch off the automatics and hand fly the missed approach procedure. Usually, clicking the GA button at 50 feet or so allows the airliner to do a fully automated go around, and do it well. Its true that the flight path will continue to sink but there is enough space to GA without touching if the procedure is done right. I've done a GA from less than 50 when a truck inexplicably drove across the runway ahead.
Im using 50 feet above the runway but CAT III was mostly based on RVR visibility than minimum altitude depending the type of approach. On every landing the radar altitude starts the auto voice reeling off the altitude...50, 40 etc the rate that the voice announces could be indication of a firm arrival.
How does this apply to GA or LSA flying? Well...flying the pattern and landing the same way each time helps as well as being on a stabilized approach. Airliners nearly always land on long and wide runways, whereas smaller planes can land on short and narrow as well as longer and wider. Maybe having obstacles and trees etc on short final too. In that regard small plane pilots need to be able to adapt and assess their arrival and potential landing point more so than airline pilots. Making the GA decision and an ego saving maneuver is never a bad thing.
Last edited by Nomore767
on Sat Aug 05, 2017 11:09 am, edited 1 time in total.