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NGFellow
1st May 2008, 02:54
After flying the B-737-200/700 for several years, I am thinking of moving over to a company that flies the B-737-900ER. Wondering if any 900ER drivers have any tips regarding landing the aircraft. I know it's a bit heavier, longer than the 700 with a 2 position tail-skid. Is the flare and touchdown technique any different.

FCS Explorer
1st May 2008, 10:31
the -800 and -900 have artificially raised app/ref speeds for F30/F40 to provide for a lower body attitude. on the 700 the diff btw F30 and F40 is about 2kts as far as i remember (i usually fly the 800, only about twice a year the 700). on the 800 (and presummably also the 900) the diff btw F30 and F40 is 7kts. this added speed is supposed to keep your pitch down. check the FCTM. the body attitude on approach is 2.0° for 600/700, 1,4 for 800 and 0.9 for 900....get the idea?
from the Touchdown body attitude tables you can see that the 600/700 @F30 has about 6°-7° while the 900 only has 4-4,5°. also the 600/700 tailstrikes a 12, the 900 at 8 (T/O likewise).
not sure if mentioned in text, but obviously the longer models require a shallower flare.

empati
1st May 2008, 11:04
No! The technique is the same both on takeoff and landing on all 737. The feel might be different, but the picture the same.

None of the airplanes should be rotated too fast. Even in the 600 there should be a gentle rotation. One should be minedful though not to over-rotate the 400, 800 and the 900.

Landing. As Boeing states, start at 50', gently retard the throttles to be idle at touchdown. However this depends on the windconditions, gust etc. Like in all airplanes, the flare is only a reduction of the sinkrate until touchdown. "Holding it of" in the flare is wrong, and often result in hard landing, tailstrike and less runway available.

Empati

RAT 5
1st May 2008, 11:29
The B738 & B739 are long a/c. There is very little flare. True, you have to arrest the ROD, but this is a more gentle and intuative manoeuvre. The B733 & B737 are shorter and allow more of a flare without driving the wheels into the deck. Try this technique on the longer a/c and it bangs in. Now, before you start, I know that the a/c rotates around the longtitudinal axis in the flare, and the wheels are pretty close to it. All I can say is, from experience, there is a difference.
To say all B737's land the same is over simplistic.

empati
1st May 2008, 15:28
Not the longitudinal axis, but the lateral axis! Now I know why your landings are hard, and off the centerline!:p

Seriously! What I am saying is, the basics are pretty much the same. But the amount of pressure on the contol column differ. Like in a helicopter, if you think of what to do with the controls, you crash! Rather concentrate about the goals, and you will succeed! The basics we all know! :8 This works even in a square parachute landing. It's timing! :p

Simplistic, maybe?! Keep it simple, stupid!:ok:

Empati

Crossunder
3rd May 2008, 12:45
As empati almost correctly points out - the a/c rotates (flares) - not only about the lateral axis, but about the CG. One should think. However; during a flare, especially a desperate save-the-day-flare, the instantaneous point of rotation is not about the CG. A long B737 will usually rotate about a point ahead of the CG. If you attach a spring to a model aircraft; right above the CG, and push quickly down on the tail, you´ll see the spring extend. This extension will be greater on a 738 than on a 733. This ´cause og th elonger distance (arm) btwn CG and tail. The undercarriage usually sits behind the CG, and a rapid flare will further increase the arm between the undercarriace and the point of rotation. You just make a bad situation worse.
So, as RAT 5 has expertly observed; even though the distance btwn CG and undercarriage on the 733/738 is pretty much the same, the longer CG-tail arm on the 738 will cause a geater down-force on the undercarriage. A forward push on the column is thus more likely to save the day than is a "traditional" flare.
I used to fly the Dash-8 300 and Q400. Same-same, but different. An extra 5-7 kts on short final always did the trick on the Q400 :ok: