737-400 approach speed
Joined: Apr 2010
Posts: 0
Likes: 0
From: Home soon
I could go on about what speed you should be over the numbers but I think it would be wasted on you.....suffice to say you should not always be at Vref
the 1kt for the grandma was not a serious comment but obviously you took it seriously..maybe some should chill out...
Concerning CRM...dont know what this came from...
The common sense was directed to me so i thank you for it
,not an attitude problem just being polite
Thread Starter
Joined: Jul 2004
Posts: 73
Likes: 0
From: Yellow submarine
de facto
I understood that you were kidding about the 1kt for grandma hence I made the joke about what TRTO she worked at. I guess only I found that one funny. Maybe I have misunderstood what you have written ref common sense class
The objective of this thread was to find out why you would constantly fly vref +8kts (nil wind) to the flare in a 400 when I can't find any reference to it. Not to debate with you if my scan is up to speed or if I can maintain a speed. I'm sure it's not as good as you think yours is.
As has been said it may just be he requires this as his comfort factor. I can live with this conditions permitting. So if you know where this is written down please let me know.....If not I will take it as the comfort factor even though I may not be flying.
J
I understood that you were kidding about the 1kt for grandma hence I made the joke about what TRTO she worked at. I guess only I found that one funny. Maybe I have misunderstood what you have written ref common sense class
The objective of this thread was to find out why you would constantly fly vref +8kts (nil wind) to the flare in a 400 when I can't find any reference to it. Not to debate with you if my scan is up to speed or if I can maintain a speed. I'm sure it's not as good as you think yours is.
As has been said it may just be he requires this as his comfort factor. I can live with this conditions permitting. So if you know where this is written down please let me know.....If not I will take it as the comfort factor even though I may not be flying.
J
Joined: Apr 2010
Posts: 0
Likes: 0
From: Home soon
Theres is no mention of this vref+8 kts app speed in any manual.
Even for older classics with bent wings(ie not that smooth) an increase of app speed is not mentionned as far as i know.
It is up to you as a PF to follow boeing procedures(fctm).
If your training captain or TRI teaches you to add these few knots,just do it for CRM...once you will be captain you will decide and act by your own judgement.
It doesnt hurt to ask the person in question why he does so(for all other issues too),then you will decide for your own.
Obviously the FCTM is clear.
In real world,(ie not sim),you will see that most pilots arrive into the QRH flare area of 50 ft at app speed(vref+5 mini or vref + gust) as being at vref exactly at 50 ft needs quite a good skill and any change of wind or retarding the levers just bit too quickly may get you below vref.
So some accept a 5 kt extra speed knowing their landing distance based on a/b setting/weight/rwy condition.....
If you are close to your max ldg distance available then id make sure to be at vref.
Not being below vref is important as it is your minnimum speed for flaps retraction.
At the end of the day we all try to be as precise as possible but when theres room,one may accept a comfort margin...
Good day.
Even for older classics with bent wings(ie not that smooth) an increase of app speed is not mentionned as far as i know.
It is up to you as a PF to follow boeing procedures(fctm).
If your training captain or TRI teaches you to add these few knots,just do it for CRM...once you will be captain you will decide and act by your own judgement.
It doesnt hurt to ask the person in question why he does so(for all other issues too),then you will decide for your own.
Obviously the FCTM is clear.
In real world,(ie not sim),you will see that most pilots arrive into the QRH flare area of 50 ft at app speed(vref+5 mini or vref + gust) as being at vref exactly at 50 ft needs quite a good skill and any change of wind or retarding the levers just bit too quickly may get you below vref.
So some accept a 5 kt extra speed knowing their landing distance based on a/b setting/weight/rwy condition.....
If you are close to your max ldg distance available then id make sure to be at vref.
Not being below vref is important as it is your minnimum speed for flaps retraction.
At the end of the day we all try to be as precise as possible but when theres room,one may accept a comfort margin...
Good day.
Joined: Mar 2011
Posts: 1,407
Likes: 0
From: engineer at large
Autothrottle on the 737 set at Vref +5kts. 8kts is the gust value.
why would you do that? this makes no sense, first off, you would have to disengage the AT, and you are likely on idle descent... 
One airline I've flown at used Vref+10 as the minimum for RNP approaches. That was for -4,7,8, and 900s.
Joined: Oct 2006
Posts: 658
Likes: 1
From: Ankh Morpork, DW
why would you do that? this makes no sense, first off, you would have to disengage the AT, and you are likely on idle descent...
I believe it was to prevent an underspeed-->level change reversion.
And why would you need to disconnect A/T?
Joined: Mar 2011
Posts: 1,407
Likes: 0
From: engineer at large
I'd like to see this 'book' on RNP.
They may have "wrote the book" or "cooked the book"...its a fine line, as I am not sure to whom you refer. There are many of us who have fixed that book.
Your post combined classics and NG...so I am wary of your context.
Fly a 900 at 3 degrees at Vref+10 and manage that energy on AT..(AT?)
On RNP, the auto throttle is engaged, so for one to 'fly' at Vref+10, one implies the AT has been degraded.
Another option to attain Vref+10 would be use CAT D for RNP on the 737...
So, many options or avenues...
lets open that 'book'
They may have "wrote the book" or "cooked the book"...its a fine line, as I am not sure to whom you refer. There are many of us who have fixed that book.
Your post combined classics and NG...so I am wary of your context.
Fly a 900 at 3 degrees at Vref+10 and manage that energy on AT..(AT?)
On RNP, the auto throttle is engaged, so for one to 'fly' at Vref+10, one implies the AT has been degraded.
Another option to attain Vref+10 would be use CAT D for RNP on the 737...
So, many options or avenues...
lets open that 'book'
Joined: Oct 2006
Posts: 658
Likes: 1
From: Ankh Morpork, DW
In 1996, Alaska Airlines became the first airline in the world to utilize an RNP approach with its approach down the Gastineau Channel into Juneau, Alaska. Alaska Airlines Captain Steve Fulton and Captain Hal Anderson developed more than 30 RNP approaches for the airline's Alaska operations.
Required navigation performance - Wikipedia, the free encyclopedia
The Vref+10 is only for the -400 now. I see that the procedure was amended after my company-provided 2-year+ vacation. So for the NG it is Vref+5.
I'm still not sure why you mention disconnecting the A/T.
Joined: Aug 2008
Posts: 666
Likes: 0
From: Betwixt and between
I'm still not sure why you mention disconnecting the A/T.
I can't get my head around what VREF+10 has to do with RNP either??
Joined: Mar 2011
Posts: 1,407
Likes: 0
From: engineer at large
I'm still not sure why you mention disconnecting the A/T.
Vref+5 is AT...Vref +10 is not
I am very well versed in the Naverus (Alaska Airlines) criteria.
150kts was used on very few final approaches, namely PSP..and it doesnt work for anything but a 400...
Joined: Oct 2006
Posts: 658
Likes: 1
From: Ankh Morpork, DW
I can't get my head around what VREF+10 has to do with RNP either??
RNP is not autoland.
Last edited by ImbracableCrunk; 26th April 2011 at 04:42.
Joined: Oct 2006
Posts: 658
Likes: 1
From: Ankh Morpork, DW
Vref+5 is AT...Vref +10 is not
Maybe it's this -At ALK for VNAV minimum wind correction for the -400 is 10. The approach is flown LNAV, VNAV, A/P and A/T.
The approach is flown with the MCP speed window closed - flying at Vref+10 - until visual conditions.
No need to fly with the A/T off.
