Simple question regarding Vref and Vref + Factor

[zmiller4]

Fine, leading. . .wrong word.

There is little debate within the NTSB, and obviously the FAA (thanks to AC 91-79) that excess airspeed is a contributing factor in turbojet overruns.

Excess airspeed...as in Southwest in Burbank. Again, I think that a normal gust correction of 5kts isn't going to run you off the runway--in fact, it's within both ATP standards and tolerances of most SOP's.

With that being said, I agree that in certain situations such as gusty winds maintaining a safe airspeed is clearly important but so is touching down in the TDZ as opposed to floating it 7/10th of the way down the runway.

Absolutely.

But, if the FAA didn't think people were flying planes without a due regard to effective speed management I don't see why they would have published AC 91-79. Figured since we have been lacking any respectable technical threads here in the Airline Pilot section that this would have been a great opportunity to dig deep into what we all have been doing.

Good idea!

First off, with all due respect to the Feds, their record when it comes to appropriately addressing safety issues isn't that great (the current CRJ200 AD's and procedural changes are a great example). I think you might be focusing a bit too much on the AC's paragraph on Vref. When I read it, I took it to be much more about stabilized approaches and landing distance requirement calculations. But you're right, they do specifically mention crossing the threshold at Vref. My company changed our speed cards and SOP to reflect an approach speed of Vref (+1/2 gust) rather than Vref+5 (probably in response to AC 91-79). Even before with Vapp at Ref+5, the tecnique that was generally taught was to start backing off the power at 100' to have it idle at 50' (which would get you to Vref at 50')

I make an effort now to discuss this with Captains following an approach brief where they indicate we will be crossing the fence at Ref+5...Maybe I'm just anal

No comment.

I definitely see your point, but the argument around Vref vs. ref+gust factor to me is a far, far less important one than whether or not we actually know when to and actually use landing distance calculations. How many people do you think re-calculate landing requirements every time conditions vary from the release? Or can rattle off every condition that precludes use of LAHSO?

 

[surreal1221]

As far as that last paragraph. No clue, you're right.

But, some how we still make it happen without planes coming up short or going off the end in excessive numers (more than 0 is excessive ).

Anyway...I just hope that because of this thread those who had no clue about AC 91-79 managed to open it up and take a look at ALL the factors that the FAA deemed prudent to place into the AC.

 

[Polar742]

But, if the FAA didn't think people were flying planes without a due regard to effective speed management I don't see why they would have published AC 91-79. Figured since we have been lacking any respectable technical threads here in the Airline Pilot section that this would have been a great opportunity to dig deep into what we all have been doing.

I've heard numerous Captains over the past few months referring to crossing the fence (50ft) at Vref+5 (I understand Ref +5/-0 deal. . .no worries there)

After I read 91-79 a few weeks back I managed to print a copy out as well as take a closer look at our procedures and realized that I myself have been trained incorrectly. We were "Trained" in the box to fly Ref+5 all the way down to 50ft where we reduce the throttles to idle.

I make an effort now to discuss this with Captains following an approach brief where they indicate we will be crossing the fence at Ref+5.

Maybe I'm just anal, but I don't feel the need to go off the end. *shrug* I just think by emphasizing Vref at 50ft it makes an effort to remind people that too much excess speed can have significant impacts when operating into smaller fields. That's all.

Good for you for finding an AC. Unfortunately, that is but one piece of information for the giant puzzle.

The swipe that everyone who has been flying Vref+5 for YEARS and your implication that the FAA thinks wer're all flying without due regard to airspeed management is dumb and arrogant.

If you think Vref+5, as you are trained will run you off the end of the runway, as indicated in your last paragraph, you don't know very much outside of the AC circular you read.

Have you read all the other pieces of information that contribute to Part 25 turbojet performance? I doubt it. I've been in the office working on that stuff and was quite fluent at it, however I still learn stuff everyday.

After one year online after flight instruction, it's great that you are digging up information and learning. Remember that there are alot of people out there who have also read that info. Probably the FAA Inspector that certified the CL-65, the Inspector that certified ASA's training program, the Inspector that signed off the vendor for the performance data, and maybe some of us that fly without due regard to airspeed control have also read that.

 

[400A]

REF+5

REF is toooooo slow. By the time you're at the 1000 ft markers you're looking at REF-10 or REF-15.

DANGEROUSLY slow.

I think you are being just a bit dramatic there. Ref is roughly 25 to 30% above stall speed in the landing config, at 100 knots that gives you a stall speed of 70 to 75 knots and touching down (by your math) at 85 knots is anything but DANGEROUS. If you have applied all of your gust factors as required you are in no danger of falling out of the sky. Fly the airplane, on speed, on centerline and on glidepath and all will work out (helps if you flare too).

There are other factors that will increase your landing distance, coming in too shallow, carrying power to touchdown (turbo jets), floating, etc. Speed is only one small part of the puzzle.

 

[surreal1221]

Good for you for finding an AC. Unfortunately, that is but one piece of information for the giant puzzle.

Thanks, and you're correct.

The swipe that everyone who has been flying Vref+5 for YEARS and your implication that the FAA thinks wer're all flying without due regard to airspeed management is dumb and arrogant.

Okay dokey. . .show me where I showed that everyone who flys Vref+5 is doing it without due regard to airspeed management. I love how this thread was progressing and thoughts about what was going on were being provided. Now I'm a little taken aback by your statement which is no where near anything I've said in this thread, or so I don't think I have said.

I did not say anyone was flying without due regard to airspeed management, but that the FAA certainly felt the need to emphasize proper airspeed management. Regardless of how I felt.

If you think Vref+5, as you are trained will run you off the end of the runway, as indicated in your last paragraph, you don't know very much outside of the AC circular you read.

I said flying Vref+5 would run me off the end of the runway? You sure?

My emphasize is that proper airspeed management - as indicated by many training materials - will minimize overruns. Not that I expect to go off the edge of a runway at Vref+5. Hopefully that clears that up, if not, fine so be it. Sure it won't be the last time.

Have you read all the other pieces of information that contribute to Part 25 turbojet performance? I doubt it. I've been in the office working on that stuff and was quite fluent at it, however I still learn stuff everyday.

That's fine that you doubt my ability to read material. Not that I really care or that I think you really care either, but yes I have spent a few hours over the past few months reading Part 25. Perhaps not to the experience level you would like me to see, and I'm not trying to be an expert on the subject.

What you are doing is exactly what I'm doing. Learning new stuff everyday. I suppose now you'll tell me that us little guys should just stick to being quiet over in the right seat too huh? :crazy:

Nevertheless, how about tell me why I'm wrong in regards to excessive airspeed outside of conditions that recommend additional additives added to Vref. Tell me why my opinion that excessive airspeed is wrong, help me learn. Or, are you going to tell me to go search it out on my own? I don't know, but if my opinions are so wrong why not try educating me so I'll learn something as opposed to being told I lack the experience to hold an opinion on the subject.

After one year online after flight instruction, it's great that you are digging up information and learning. Remember that there are alot of people out there who have also read that info. Probably the FAA Inspector that certified the CL-65, the Inspector that certified ASA's training program, the Inspector that signed off the vendor for the performance data, and maybe some of us that fly without due regard to airspeed control have also read that.

Yes, my single year of being on the line. Clearly I lack the experience required to recommend this topic for discussion. Gets back to learning new stuff everyday and bringing up topics that I thought I was familiar with, and ultimately procedures and practices that I had been trained on. Such a horrible thing I know right?

My single initiative was to generate a discussion concerning AC 91-79 coupled with the various turbojet overruns that have occurred. Hopefully THAT discussion continues. If not, then it'll be a disappointment to see that we can't have technical discussions here on JC.

BoldedOnce again, that last sentence strikes me a little raw. I'm not even coming close to saying anyone is flying without due regard to proper airspeed management (at least in regards to Vref+5).

I would expect most professional pilots would consider excessive airspeed outside of gusty conditions to be an unsafe practice, perhaps I'm wrong. Figured that would be something all of us could agree on.

But anyway, I hope this thread can continue the discussion of who has the appropriate experience requirements to debate such topics.

Enjoy the office work I suppose.

 

[zmiller4]

Okay dokey. . .show me where I showed that everyone who flys Vref+5 is doing it without due regard to airspeed management.

I did not say anyone was flying without due regard to airspeed management, but that the FAA certainly felt the need to emphasize proper airspeed management. Regardless of how I felt.

I said flying Vref+5 would run me off the end of the runway? You sure?

My emphasize is that proper airspeed management - as indicated by many training materials - will minimize overruns. Not that I expect to go off the edge of a runway at Vref+5.

Surreal, the title of the thread/poll is Vref vs Vref + Factor. You're talking the whole time about captains who fly Vref + 5 or Vref + gust to the threshold. While you're not saying specifically that represents poor airspeed management, consistently bringing up excessive speed in a thread about flying 5 knots (up to 10kts for wind) fast sure implies that those that do are doing something wrong.

I would expect most professional pilots would consider excessive airspeed outside of gusty conditions to be an unsafe practice, perhaps I'm wrong.

That's not what your poll is about though, right? It's about adding airspeed for gusty conditions, correct? I think that's where people are getting confused/annoyed here. Everyone knows excess airspeed is bad; but is 5 kts really "excess airspeed"? If not, it sure seems like you're lumping it in with the sort of excess airspeed that causes overruns. I can understand why that might be annoying to folks who work in training depts with these sorts of numbers everyday.

The fact that the FAA chose to include it in an AC doesn't necessarily mean much, either. They focus on a lot of BS. I could get my certificate suspended for doing all the jepp revisions for my trip but carrying the rest with me to finish in the air (but 16hr days and 250hr airline pilots are A-OK!).

 

[mikecweb]

I haven't read this whole thread and I won't comment too much as I would be torn apart by the 121 crowd on how I/we operate our turbojets but I'd like to add that speed isn't everything also landing in the touchdown zone is very important.

 

[surreal1221]

That's not what your poll is about though, right? It's about adding airspeed for gusty conditions, correct? I think that's where people are getting confused/annoyed here. Everyone knows excess airspeed is bad; but is 5 kts really "excess airspeed"? If not, it sure seems like you're lumping it in with the sort of excess airspeed that causes overruns. I can understand why that might be annoying to folks who work in training depts with these sorts of numbers everyday.

The fact that the FAA chose to include it in an AC doesn't necessarily mean much, either. They focus on a lot of BS. I could get my certificate suspended for doing all the jepp revisions for my trip but carrying the rest with me to finish in the air (but 16hr days and 250hr airline pilots are A-OK!).

No, the poll is about the basic question regarding no additional speed additives in relation to gusty winds. It is the simplest form of the question.

That was the foundation of the discussion, hoping to move further towards discussion regarding airspeed management in overrun situations / incidents / accidents.

No winds, no gusts. Vref or Vref+5 across the fence. Just to be clear, 5kts is not (IMHO) excess airspeed.

And yes, we should ignore stuff from the FAA because it's useless.

That blasted Airplane Flying Handbook is junk! So is that silly Fundamentals of Instruction handbook. Toss it! Those FAR's, BURN THEM!

Who else should we trust to do these studies? Private industry? A co-operative between Private Industry and the Government (which occurs)?

Nevertheless, the data is provided, and I don't think it should be ignored. Especially for individuals like myself who's only jet experience was through a 121 Ground and Initial course that didn't provide much of anything in regards to turbojet or sweep wing aerodynamics. I'm thankful someone has data out there for people in my position, who have the initiative to learn more, to evaluate.

 

[Polar742]

After I read 91-79 a few weeks back I managed to print a copy out as well as take a closer look at our procedures and realized that I myself have been trained incorrectly. We were "Trained" in the box to fly Ref+5 all the way down to 50ft where we reduce the throttles to idle.

I make an effort now to discuss this with Captains following an approach brief where they indicate we will be crossing the fence at Ref+5.

Maybe I'm just anal, but I don't feel the need to go off the end. *shrug* I just think by emphasizing Vref at 50ft it makes an effort to remind people that too much excess speed can have significant impacts when operating into smaller fields. That's all.

If you read the above, and can't figure out where the implication of Ref+5 = dangerous in surreal's mind is, I can't help you. If you can't figure out why what you wrote would piss off a Captain, or FO when you upgrade, you need to think on it for a bit.

You really project an attitude that you are smarter than all of us, and quite frankly it's grating and comes across as a high level of arrogance.

It's readily appearant that while you have a good toolbox of knowledge, you don't have the ability to put it all together in a manner that, frankly, doesn't piss most people off.

Your amount experience doesn't invalidate your opinion, but you REPEATEDLY refuse to listen to anyone who has similar or more knowledge and has experienced it in practice in many situatins that you just haven't had in your career. It's not a slice to you personally, but is a reflection of where you are on the continuum. You are still at the point where you need to contemplate and reflect what people tell you.

Further, you put up an opinion. If someone with more knowledge and experience (in technical discussion, as much as you'd like to think otherwise, they can't be separated) contradicts what you think is right, or writes something you don't agree with, you write a condensending post thown with a bunch of and *shrug*.

There is a wealth of experience on this site, and a knowledge base of some amazing posters that I've got to know. They contribute their knowledge and, most importantly, their APPLICATION of the knowledge via their experience. And they do it for FREE. I only hope to be on par with that group one day.

As far as the office work, I've explained my experiences and career path in previous threads. The only reason I pointed that out was to emphasize that I have written manuals and training programs and done the myriad of things that I talked about. It's not a book I read, or a discussion on a web board, I was charged with part of the system safety.

 

[surreal1221]

Thanks Polar.

I'm sorry I rub you the wrong way.

It's pretty clear to me that nothing I say will be given any amount of perspective in regards to this discussion.

I'm not trying to challenge people's skills, procedures, or techniques. Simply a friendly discussion concerning some things I found. Which it appears to some at least, is not possible.

But clearly, I'm just some condescending kid that must challenge everything someone else says. At least in your eyes. The only person it appears I've pissed off in this thread is you. Unless there are others in the woodwork? zmiller, have I pissed you off?

To help me Polar, please find the opinions that you're telling me I'm forcing onto people and let me know how I'm being condescending and not considering the input by others? Also, if you have the time, educate me and inform me. If it's not obvious, my ears are wide open and would love to learn something.

 

[zmiller4]

I haven't read this whole thread and I won't comment too much as I would be torn apart by the 121 crowd on how I/we operate our turbojets but I'd like to add that speed isn't everything also landing in the touchdown zone is very important.

Totally agree.

No winds, no gusts. Vref or Vref+5 across the fence. Just to be clear, 5kts is not (IMHO) excess airspeed.

That was the foundation of the discussion, hoping to move further towards discussion regarding airspeed management in overrun situations / incidents / accidents.

If the poll isn't about excess airspeed, then what relation does it have to overrun accidents?

To answer your question, I try to cross the threshold at Vref because that's what we bug. Unless it's gusty, and then we bug Vref + 1/2 gust factor, in which case I do what I need to to put it down on the mains, in the touchdown zone, on centerline, with the longitudinal axis of the airplane parallel to the aircraft's direction of movement, just like when I was a private pilot.

I would never call out a captain for wanting to cross the threshold at Vref + 5. I'm not afraid to call out a captain on a meaningful safety or administrative issue, but there's no way I'd piss someone off over 5kts. It's not worth it.

Those FAR's, BURN THEM!

What FAR's am I advocating ignoring? And does the AC even specifically state that the threshold should be crossed at an aircraft's Vref, not +5?

I guess my question to you would be:

What is the point of the poll? Everyone knows excess airspeed is bad. 5kts is, according to you, not excess airspeed. So what's the point here? Honestly, if you can control your airspeed that accurately 100% of the time then you're better than anyone I've flown with.

 

[surreal1221]

I'm not advocating anyone calling anyone else out.

The point was to put AC 91-79 out there for people to take a look at. Now if it happened, great. If not, fine. So be it.

You're not advocating ignoring any FARs, it was sarcastic. Trying to lighten the mood around this thread.

 

[zmiller4]

zmiller, have I pissed you off?

No, but 4 of my 5 legs got cancelled so I'm sitting happy in a nice hotel room at the 4 Points watching ORD self-implode.

I think the problem is that you're combining 2 different issues: 1--not many people know that their SOP's might specify crossing the threshold at Vref instead of Vref + something, and 2--the type of out-of-control approach that leads to overruns like Southwest in BUR. I think that both are discussion-worthy, but talking about both makes it seem like they're one and the same.

 

[mikecweb]

Hey Josh maybe you should have just posted the AC and bolded some things that you found interesting.

*shrugs*

"just my opinion"

...are all additives that take a thread from informational to personal and frankly lead people to believe that you take the subject personally. Take a step back and observe what some people are saying. You're making a mountain out of a mole hill and trying to proclaim that you've found a major issue with flying technique that'll save lives some day. I think it's arrogant to believe that telling people that 5 knots will cause overruns and throwing references like they have no knowledge of the situation.
Maybe it was just me but I was exposed to this subject well before I burned Jet-A. Swept wing aerodynamics was taught during my worthless studies at Riddle.

 

[surreal1221]

I didn't have the pleasure of attending Riddle, perhaps that's my problem.

And mike, trust me brotha. I'm not taking this thread personally. I do though, take what an experienced aviator (Polar) says regarding my attitute personally though. Especially when I feel it's a little unwarrented.

 

[Trip7]

After I read 91-79 a few weeks back I managed to print a copy out as well as take a closer look at our procedures and realized that I myself have been trained incorrectly. We were "Trained" in the box to fly Ref+5 all the way down to 50ft where we reduce the throttles to idle.

I make an effort now to discuss this with Captains following an approach brief where they indicate we will be crossing the fence at Ref+5.

Maybe I'm just anal, but I don't feel the need to go off the end. *shrug* I just think by emphasizing Vref at 50ft it makes an effort to remind people that too much excess speed can have significant impacts when operating into smaller fields. That's all.

You're being anal. Your captains must have been looking at you crazy for discussing 5 knots. If you fly ref+5 and touchdown on centerline, on speed, in the touchdown zone you will not run off the end of the runway unless you lose the brakes.....

And no you weren't trained incorrectly....

 

[kellwolf]

And if you fly it at Vref instead of Vref+5, you won't fall out of the sky. I've done it 7 times this week. I didn't even get the shaker.

 

[400A]

And if you fly it at Vref instead of Vref+5, you won't fall out of the sky. I've done it 7 times this week. I didn't even get the shaker.

You're doing it wrong....

 

[jtrain609]

Hey so has anybody flown the EMB-145 and the CRJ-200?

Because from the sounds of it, the CRJ-200 is an absolute #### box of an aircraft if you can't fly ref+5 to about 50' without the thing sliding off the end of the runway. I mean, are the brakes, ground spoilers and TR's really that useless on that thing? Or are your speeds just so high as to cause you to go flying off the end of the runway if you're a few knots fast (TVC).

I mean in my mind some of this stuff wasn't even an operational concern. You fly the speed that the book tells you to fly, you land, and you stop in the distance the book said you would. You park, go to the overnight and have a beer. Seems pretty cut and dried to me.

 

[Rocketman99]

Yeah, but you're (mostly) all advocating flying faster than you need to/are supposed to. That's the problem. OK so ref +5 isn't a big deal. Ok, so you're shooting for that but now you're flying ref +10 or 20 trying to correct to it. That's where the problem is. Fact of the matter is, you're not even remotely close to falling out of the sky at ref. What, it's 1.3 times stall speed or so. Even with a gust you're not remotely close to falling out of the sky at ref, so you're advocating flying fast for no reason. Now if your company's procedures/told data tell you otherwise great. However, if you're adding extra speed for mom and apple pie you're hurting rather than helping yourself, especially in adverse conditions. Seems like people tend to forget that ref speed already gives you a HUGE cushion above stall speed. Short of flying into a hurricane you would never be close to a stall flying AT ref.