Hard Landings: are they useful?
Join Date: Jun 2003
Location: las vegas
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TYKON SAID:
To used2flyboeing,
Yes, you're correct about the magnetic sensors etc, near/far, all that crap....BUT...it doesn't make an ounce of difference if you touch softly, or dump it down. The sensors are set into ground mode, or air mode, when the torsion links on the gears compress or extend. There is no thinking in the system, either it is on the ground or not. On the B737Ng, there are 2 sensors on each gear, and between them they work out if the aircraft is still in the air, on the ground or back in the air etc. All the sensors go to the PSEU to be sorted out.Depending on the combination of gears that are compressed/extended, as to what it allows to happen with the anti skid/aquaplaing and so on protection.
..all that crap..., does make an ounce of difference if you understand how the system is designed .. I was more speaking to 75 & 767 that use truck tilt sensors in addition to squat switches - Boeing has gone to great lengths to work out ground logic based on in service problems - IE the non-uniform piloting / landing techniques the world around have never failed to confound the logic of the PSEU system. Boeing has used a permutation of truck tilt, MLG & NOSE Gear squat switches & even Inertial reference to sort this out. I know the 757s with the 13 degrees of truct tilt - would pop out of ground mode if you did a bounce on landing - & guess what, it would pop out of autobrakes as well ! On some 737s if you did a very smooth landing you would not get any spoiler or reverse thrust b/c the PSEU could not detect a disticnt transition - all this stuff has been fixed - but the result at Boeing Flight Training - at least back in the early 90's was to do crisp air to ground transitions ..
To used2flyboeing,
Yes, you're correct about the magnetic sensors etc, near/far, all that crap....BUT...it doesn't make an ounce of difference if you touch softly, or dump it down. The sensors are set into ground mode, or air mode, when the torsion links on the gears compress or extend. There is no thinking in the system, either it is on the ground or not. On the B737Ng, there are 2 sensors on each gear, and between them they work out if the aircraft is still in the air, on the ground or back in the air etc. All the sensors go to the PSEU to be sorted out.Depending on the combination of gears that are compressed/extended, as to what it allows to happen with the anti skid/aquaplaing and so on protection.
..all that crap..., does make an ounce of difference if you understand how the system is designed .. I was more speaking to 75 & 767 that use truck tilt sensors in addition to squat switches - Boeing has gone to great lengths to work out ground logic based on in service problems - IE the non-uniform piloting / landing techniques the world around have never failed to confound the logic of the PSEU system. Boeing has used a permutation of truck tilt, MLG & NOSE Gear squat switches & even Inertial reference to sort this out. I know the 757s with the 13 degrees of truct tilt - would pop out of ground mode if you did a bounce on landing - & guess what, it would pop out of autobrakes as well ! On some 737s if you did a very smooth landing you would not get any spoiler or reverse thrust b/c the PSEU could not detect a disticnt transition - all this stuff has been fixed - but the result at Boeing Flight Training - at least back in the early 90's was to do crisp air to ground transitions ..
