737-400 approach speed

[jidder]

Has anyone heard of a technique of adding 8kts to the approach speed instead of the recommended 5kts, In conditions where the reported wind speed is Variable less than 10 including tailwind.

I was told that this is a requirement on the 400. I can't find this in the FCOM.

Thanks,

J:E

[ImbracableCrunk]

That sounds odd. So if it was a 10 knot headwind, you'd add 5knots. But if it was variable at 10, you'd add 8 knots?

I've got 734 time and I've never heard of it.

[jidder]

I was told for any wind reported under 10 kts the approach speed was to be flown Vref+08kts!

I have never heard of this before, would there be any reason or justification for this?

J:E

[ImbracableCrunk]

Hmmm. That's not in any of the references I have from two airlines. One airline I've flown at used Vref+10 as the minimum for RNP approaches. That was for -4,7,8, and 900s.

Otherwise it's from the FCTM and that is the standard.

[jidder]

That's what I thought.

I have flown the 6,7,800 and all my classic time on the 400 and never heard of such a thing! Hence my post here.....

It's in the FCTM and I will be sticking to the +5kts unless the wind dictates different.

Thanks,

J :E

[BOAC]

Do you have an Ops Manual?

[jidder]

BOAC

Yes and there is no mention of it. I thought that it may be a technique that I hadn't been told about.

It makes no sense to carry extra speed when not required. My company operates into alot of high elev airfields. 5000-6000 ft so this would give a higher GS over the numbers. I wouldn't like to have an over run.:sad: Not that the 3Kts would cause that.....

J:E

[jidder]

Should have mentioned hot too!

J:E

[BOAC]

Thought I would ask, since most Ops Manuals TELL you how to bug speeds and that is what you should be doing! Traditionally on Boeing it is half the speed plus all the 'gusts' so I guess you could derive + 8 in some circumstances but not as an SOP.

[jidder]

No standard Boeing. That is why I wondered about the Vref +08kts in nil wind!

I guess it must just be his own aditive for the wife and kids:suspect:

Thanks for your input......thought I was missing something somewhere.

J:E

[BOAC]

How many wives and how many kids.......?:D Perhaps particular pilot is 'frightened' by the thought of flying SO SLOWLY..............:confused:

[Tee Emm]

Traditionally on Boeing it is half the speed plus all the 'gusts'

Presumably you mean half the reported headwind component plus all the gust factor? Not forgetting the FCTM advice to bleed off the headwind component approaching touch down. Many airlines fail to accentuate this point and the result is excess speed over the threshold and long float which is not a Good Thing - especially if runway length limited and its raining.

[BOAC]

Presumably you mean half the reported headwind component plus all the gust factor? - indeed - hopefully 'abbreviated' for those who understand:ugh:

[jidder]

Tee Emm

Thanks I understood exactly what BOAC was talking about. The thread was reference to why would you set Vref +8 as standard instead of Vref +5 as recommended inthe FCTM.

I also understand that you have to maintain the gust factor if applied whilst removing the mean wind component.

I guess it's like BOAC says ....this guy doesn't like to fly the recommended speed and would like to use more runway! All good and well on long runways:suspect:

J:E

[de facto]

check your QRH and see the landing distance difference for an increase of 3 kts...cant be that much..maybe 30 m? if you keep it until touch down..
I normally add one kt but thats for my grandma..

[jidder]

D Facto

What TRTO does your grandma work at:}

Maybe one day that 60m will be required....why fly faster than required?

Do you Increase your V1 because you feel like it? Why not depart with a 13kt tailwind.

We don't have to be so rigid with the numbers but common sense dictates.

J:E

[Denti]

Increased V1 and/or Vr is actually a boeing standard procedure for improved climb out performance. As much as up to 35kts is perfectly normal.

[jidder]

Yes Denti.....

If the figures tell you that your V1 for an Improved climb is 168kts you don't go adding 3 kts cos you feel like it do you?

That was my point.

My original question was why would you set 3kts faster than the boeing recommended Vref +5kts for nil wind conditions.

End of! Thanks

J:E

[de facto]

Do your SOPs dictate to use A/T OFF for app/landing with A/P oFF??
Maybe the guy just doesnt trust you can fly vref+5 so accurately..and believes adding 3 kts to the APPROACH speed (which will be bled off) during flare is a safer option to start with or when you scan and reaction arent as quick as they used to be...

TO answer your question: APPROACH SPEED does NOT affect your landing distance!
You must plan to be at VREF and stay there from 50ft to touchdown...the speed you fly before this gate is irrelevant.

f the figures tell you that your V1 for an Improved climb is 168kts its not V1 that you increase,,,its V2...but v1 and vr get dragged along...

but thanks for the COMMON SENSE class...:rolleyes:

[jidder]

De Facto

Why the attitude? Great CRM...

The chap who advised me to fly Vref +8 also does this himself, so maybe it is just you who thinks I can't fly the aircraft at the command speed.....

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:ugh:

The sorry thing about COMMON SENSE is it's not very common anymore. You are a prime example!

Have a nice day.....

J:E

[de facto]

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

Correct ,you see I give you some credit knowing gust should be added till touchdown even though you see baffled by someone adding a few kts while you know the boeing a/t restrictions.

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:rolleyes: ,not an attitude problem just being polite:E

[jidder]

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:rolleyes:

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.:suspect:

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.:ok:

J:E

[de facto]

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.

[FlightPathOBN]

Autothrottle on the 737 set at Vref +5kts. 8kts is the gust value.

One airline I've flown at used Vref+10 as the minimum for RNP approaches. That was for -4,7,8, and 900s.
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... :=

[ImbracableCrunk]

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... :=

Well, since they literally wrote the book on RNP approaches, I'd guess they knew what they were doing.

I believe it was to prevent an underspeed-->level change reversion.

And why would you need to disconnect A/T?

[FlightPathOBN]

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'

[ImbracableCrunk]

In 1996, Alaska Airlines (http://en.wikipedia.org/wiki/Alaska_Airlines) became the first airline in the world to utilize an RNP approach with its approach down the Gastineau Channel (http://en.wikipedia.org/wiki/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. Yada yada yada.

Required navigation performance - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Required_navigation_performance)

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.

[Sciolistes]

I'm still not sure why you mention disconnecting the A/T.
My guess is because the speed addatives are intended for a non AT landing.

I can't get my head around what VREF+10 has to do with RNP either??

[FlightPathOBN]

I'm still not sure why you mention disconnecting the A/T.

Connect the threads..and read them.

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...

[ImbracableCrunk]

I can't get my head around what VREF+10 has to do with RNP either??

It's not so much for RNP as for the VNAV to prevent an underspeed reversion to LVL CHG. Or so I've been told. It's applicable to the -400 and not the NGs.

RNP is not autoland.

[ImbracableCrunk]

Vref+5 is AT...Vref +10 is not

I'm not sure what you're saying.

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.