Southwest joins the 21st Century!!

[geshields]

I have flown bigger Boeings that are much better than either the 737-300 or 700 in pitch control in level change (flight level change) and VNAV. I am no engineer and have no idea why, but assume there must be software differences that contribute.

Some at SWA claim that lack of autothrottles or other reasons are the culprit, but I don't think so. I have jumpseated in Cactus 73's where VNAV was properly used, but was suprised by the relatively abrupt pitch changes that I saw in comparison with a 747-400 for example. It is almost like Hal is always just a step behind. Throw out the gear in level change in a descent, and if you dont wind the speed back in the window immediately you will see some pretty hefty pitch down rates and descent rates to hold speed that other aircraft dampen out better.

Most likely because they have different boxes. I know our 737's use the Smith box and our 757, 767, and 777's use Honeywell.

VNAV (737's) works very well in the descent as long as the winds are updated and the altimeter setting is in. You only get screwed when you have 310 or greater in the descent and ATC tells you to slow and still make the crossing restriction.

 

[mannyaplus11]

Well...OK, we 'll do it...but only because you want it. <eyes rolling>

Oh, come on, feel the love, man, feel the love.

 

[HalinTexas]

I have flown bigger Boeings that are much better than either the 737-300 or 700 in pitch control in level change (flight level change) and VNAV. I am no engineer and have no idea why, but assume there must be software differences that contribute.

Some at SWA claim that lack of autothrottles or other reasons are the culprit, but I don't think so. I have jumpseated in Cactus 73's where VNAV was properly used, but was suprised by the relatively abrupt pitch changes that I saw in comparison with a 747-400 for example. It is almost like Hal is always just a step behind. Throw out the gear in level change in a descent, and if you dont wind the speed back in the window immediately you will see some pretty hefty pitch down rates and descent rates to hold speed that other aircraft dampen out better.

Excuse me?

 

[Alcatraz]

Excuse me?

I noticed that too... I think he meant "Hal" as in the Hal 9000 computer from 2001. Remember, "What are you doing, Dave?"

And HAL was just one letter each away from IBM...

 

[Alcatraz]

VNAV for T/O and climb will most likely save SWA quite a bit of fuel. For example: I've ridden SWA quite a bit and have noticed that while they set a "reduced power" for takeoff, that when climb power is set, it is an increase in power. I've never experienced that in the NG on VNAV.

The reason climb thrust is more than reduced takeoff thrust is because SWA does not use reduced climb thrust. I think the argument is actually in favor of fuel conservation (the quicker you climb, the quicker you save fuel at altitude). From what I remember of the -800 at ATA, we were supposed to select full climb thrust at 5000 feet to save gas, but nearly everyone forgot except in DCA. I kinda think using reduced climb thrust would save more money in the long run with less wear and tear, but what do I know.

VNAV and A/T have not stopped many from hand flying the airplane. It's just one more tool available to the crew. "There are many ways to skin a cat," and you can't put every contingency in the AFM (or whatever). Don't fear it, but keep an eye on it.

VERY well said.

 

[HalinTexas]

From what I remember of the -800 at ATA, we were supposed to select full climb thrust at 5000 feet to save gas, but nearly everyone forgot except in DCA. I kinda think using reduced climb thrust would save more money in the long run with less wear and tear, but what do I know.

When I was on the B757 we used to select "Climb 1" then "Max Climb" as the VS began to tail off. When I switched over to the B737 we were told to select your power, i.e. 27k, 26k, 24k, and assume your temperature and let the computer select your climb power. Still use the same procedure. VNAV schedules "max climb" somewhere around 14000'. Climbs well, just handles like a truck.

 

[HalinTexas]

The reason climb thrust is more than reduced takeoff thrust is because SWA does not use reduced climb thrust. I think the argument is actually in favor of fuel conservation (the quicker you climb, the quicker you save fuel at altitude).

I don't believe this would be the case, largely due to the fact you're not climbing at "best rate." (Or are you?) I think it's a throwback to the -200 days for simplicity and commonality, like the EFIS set up.

 

[Alcatraz]

I don't believe this would be the case, largely due to the fact you're not climbing at "best rate." (Or are you?) I think it's a throwback to the -200 days for simplicity and commonality, like the EFIS set up.

In theory we're climbing at VNAV ECON CLB speed. SWA actually has VNAV in the FMC, and I use it a ton, except that it's not an engageable vertical mode on the autopilot (unless the button cover is missing... I don't know how I know that!).

I still think the max climb power setting is for fuel conservation, but we base our climb speed on more than just best rate... we use best economy for our given cost index.

 

[CaptainKrash]

The end of the world must be near.

Nahhh, when they get ACARS that will be the sign

 

[GuppyWN]

Dude. We've had acars for years now.

Gup