confirmation on limitations

[Driver170 42]

I'm working my way through the limitations of the below link. i have stumbled across wind limits but there is 2 that i'm not sure of what its pointing too.

 

go to WIND LIMITS, in the column RUNWAY CONDITION, at the bottom you have CAT I 15 kts and CAT II or CAT III 10 kts!

 

what exactly are these referring too guys?

 

 

http://www.kitbagpubs.com/updates/737-800limitations.pdf

[scandinavian13 5,192]

 

 

what exactly are these referring too guys?

 

It's referring to the fact that there are wind limitations on the two different approach types.

 

Since CAT II and III are more sensitive in their nature (CAT I ILS terminates in a hand-flown landing, in theory, which means it's up to the pilot's own skill to handle the wind...as does a CAT II, but the limitation is imposed there because it gets you much closer to the ground), they can only accommodate a certain amount of wind. In this case, it's only been certified/demonstrated (the link doesn't mention which) to accept 10 knots of wind as a pure tailwind (meaning all tailwind with no crosswind component).

[Driver170 42]

Yes thats all understood thanks! But the link doesn't tell you what its for? Crosswind? Headwind or tailwind?

[tsp 2]

The left side of the colum tells you that it's for crosswinds.

But I'd be very cautious with these limitations as they are most probably Operator values and not the basic Boeing values.

[Driver170 42]

Might just do that instead of mixing it all up!

 

What does the term demonstrated mean...

[Spin737 102]

Might just do that instead of mixing it all up!

 

What does the term demonstrated mean...

Demonstrated means that's what the test pilots actually did in the real plane.

 

Maybe not a limitation, but some believe that if you go beyond that then you might have a tough time explaining in a court why you thought it was okay if you bang the plane up.

 

Some people think that if it's a limit then just say it's a limit.

[Driver170 42]

Thanks matt.

 

 

If you do an external air engine start your going to have like 200 kg less on the left tank compared to the right tank by the time you do a engine x bleed start on engine 2, so how do YOU equal this difference out?

[Spin737 102]

 

 

If you do an external air engine start your going to have like 200 kg less on the left tank compared to the right tank by the time you do a engine x bleed start on engine 2, so how do YOU equal this difference out?

 

200kg? I don't think it gets that bad. I think we'd probably just fix it in the air if we really needed to. I wouldn't worry too much about 200kg. Boeing has said that there's no good reason to worry about small fuel imbalances. They are more worried about screwing up the crossfeed. Personally, I guess 500lbs might be when I start to balance.

 

If you're looking at the fuel limitations and seeing the note about imbalances "must be scheduled to be zero" or whatever the quote is, I think that is old thinking and it hasn't been removed from the manual. Not 100% sure on that, but their later guidance suggests it's not important. Just keep it below 1000lbs.

[Driver170 42]

ha, got the figures wrong maybe about 50 kg its something thats bothered me but i use fs2crew so they keep care of all that with the pumps during takeoff and descent.

[Jack C 8]

If it is supposed to be scheduled to be zero, I would have my hand on the crossfeed constantly trying to equal the 2 sides!

[Spin737 102]

If it is supposed to be scheduled to be zero, I would have my hand on the crossfeed constantly trying to equal the 2 sides!

"Scheduled." I plan on them randomly going back into balance as well as they randomly go out. That's my schedule.

[Driver170 42]

This is from BOAC on pprune this guy knows his stuff, hes helped me on a few things

 

My practical interpretation of that is I ORDER fuel left and right to be equal (except for a prolonged ground APU run where I might ask for 100 extra in the left) but the aim would be to 'schedule' startup with equal wings. After that anything goes - up to 453 - including differences in tank shut-off and refueller errors. Any more than that and I would ground transfer - never had to do that yet, but I did have to 'fudge' it once with APU crossfeed.

 

In flight I have no real fixed figure. I fly with co-pilots who want to balance 100kg. I guess if asked I would say around 300kg. The actual 'out-of-trim' effect is small. Of course, there's always the old 'funny' of keeping extra in the upwind tank for landing in a crosswind..............