737 nosewheel landing / ground spoiler deployment
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737 nosewheel landing / ground spoiler deployment
The FCTM says "do not hold off the nosewheel"
I believe the reason for this is lack of braking due to slow spoiler deployment / weight not fully on wheels and a potential (with an aft c of g ) for this late deployment to cause pitch up.
Anyone confirm this...and /or add anything else.
Thanks in advaance
I believe the reason for this is lack of braking due to slow spoiler deployment / weight not fully on wheels and a potential (with an aft c of g ) for this late deployment to cause pitch up.
Anyone confirm this...and /or add anything else.
Thanks in advaance
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Holding the nosewheel off the rwy: (during normal operations).
1) serves no purpose at all.
2) increases landing distance, as there´s little to no gain in aerodynamic drag.
3) reduces directional control.
4) reduces forward visibility.
5) increases workload
6) interferes with other (useful) actions such as adjusting wheel braking to leave the rwy at certain place or to achieve the desired decel rate.
7) increases the possibility of a tail strike.
8) increases the possibility of a hard nosewheel touchdown.
9) in certain airplanes it increases the possibility of reverser ground contact.
There are probably more reasons not to hold the nosewheel off the ground.
Now that being said, I hate it when my first officers do not accomplish a normal and smooth derotation, but just let it drop to the ground and hit hard. That's not correct either.
I am sure you'll get more(and more interesting) contributions
rgds,
sw.
1) serves no purpose at all.
2) increases landing distance, as there´s little to no gain in aerodynamic drag.
3) reduces directional control.
4) reduces forward visibility.
5) increases workload
6) interferes with other (useful) actions such as adjusting wheel braking to leave the rwy at certain place or to achieve the desired decel rate.
7) increases the possibility of a tail strike.
8) increases the possibility of a hard nosewheel touchdown.
9) in certain airplanes it increases the possibility of reverser ground contact.
There are probably more reasons not to hold the nosewheel off the ground.
Now that being said, I hate it when my first officers do not accomplish a normal and smooth derotation, but just let it drop to the ground and hit hard. That's not correct either.
I am sure you'll get more(and more interesting) contributions
rgds,
sw.
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Not much point in my writing an answer, as Sudden Winds answered very well, but from what I gather, the longer its held off for, the harder it will hit when you lower it.
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The spoilers (and reversers) are linked to the main gear struts
If the rigt main strut is compressed the spoilers will deploy and for the reversers it's just one of the 2
If the rigt main strut is compressed the spoilers will deploy and for the reversers it's just one of the 2
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If you have a lot of bags only in the rear hold and / or aft distribution of pax and try to hold off the nosewheel you will get a rapid / marked pitch up as the spoilers deploy. Serious risk of tailstrike esp in 800 and 900 series. You are right to follow FCTM advice....do not hold it off. I suspect that by retaining a high angle of attack the spoiler deployment causes the large centre of pressure to move ahead of the c of g and with a tail heavy aircraft this pitch up can occur.
