Adding a 'Couple-a-Knots'

[FlightDetent]

Originally Posted by Check Airman

Well my point is that you do know which one is correct. The PFD Vls is correct

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Devil's advocate. What if today's one of the days when it's -3?

Now me playing Robin to devil's advocate: If on a given day, the displayed Vapp is Vls +5 AND at the same time the FAC is under-reading by 3 knots: should we not add +3 to cover the eventuality, making it VLS+8 at least at all times?

Will you also acknowledge that Airbus went to certain lengths and already adopted a modification for PFD, where the VLS is displayed based on FMS&LDS data, so the habit of fiddling with Vapp is eradicated systematically? Are we really smarter here than the OEM engineers and standards technical pilots, as well as the financial controller who signed for the investment needed to develop the mod?

We didn't have any short/long landing technique.

Post a picture / coordinates of your next (MLG) touchdown, dare? Or at least your most frequented landing runway.

As I stated before, if the runway length is limiting, I'm happy to let the Vapp sit on top of Vls.

That awfully sounds lot like a different technique for a short LDA, pardon my french.

Here's the point: if you are willing to fly closer to displayed Vls on a limiting rwy (please do say what lenght is limiting for you - I mean what distance), why get all excited with Vls +4 on a long runway? Why not get a practice of flaring from Vls +3: at least we'd train a bit and stand lesser chances of screwing up when shooting into a limiting LDA with Vapp sitting atop VLS, hm?

There are some seriously good points in the thread.

• measure with a micrometre, cut with an axe - what's the point (my language's own version: a precise calculation of inaccurate values)
• if suspect of the weight, work the work and brief it with S-speed data, do not start playing smart only after landing flaps is gets extended.
• the debate is academic for a day's flight, but at a grass-root systematic level quite relevant
• the certified approach speed is Vref. The additions go on top for a reason.
• sloppy flying and lazy thinking is not the target state for a professional
  
  

[icemanalgeria]

I agree with you john.
some examples are landing in HER where you have sea, cliff runway, Or MBA Trees, Valley Runway always give a sudden drop in energy at a time its not easy to recover with thrust.
I've briefed many a new copilot on possible speed loss, when we get it they ask how did you know we'd get speed loss I answer experience and now you gained that too.
An old boy told me, now i'm the old boy. I hope you young guys appreciate this knowledge as I do, and I bet as John does.

[rickseeman]

I guess this thread sums up all the excuses people use for approaching too fast. I once watched 1,000 airliners land at a major airport. Everyone one of them approached too fast and landed too long. Vref is already 30 percent above stall speed. How much do you need? Since I started flying 35 years ago very single person that has died trying to land at my home airport was trying to land way over Vref. And they all had an excuse. And these were all very experienced pilots. One of them may have been a former Air Force One pilot. These weren't dummies. But they were all (like everyone else) coming in way over Vref. And there will be at least 10 more crashes from coming in over Vref before you hear of a single crash from going too slow on final. Come in as fast as you want guys. It will be job security for the NTSB.

[Cmon-PullUP]

On the A320, a 5 kts increase in Vapp, increase ldg distance roughly 8%
Throw in a little tailwind, late flare, drift, termals and late breaking as you wish.

I am not anal about a few extra knots with all of the above considered, but I am very sure a lot of those asking for a few extra knots, haven't got a clue what the effect is. On a 2500+ m rwy it is not a problem, but it might very well be on shorter rwy's.

[pineteam]

Unless you operate in extremely short runways, Using the EFB, an A320 max landing weight at 64.5T in ISA condition and no wind will have a landing distance of only 2350M with auto brake medium with No Flaps and No Slats with a VAPP of 185kt and only 1750M with manual braking. You would have to land way past the TDZ in normal condition to overrun this aircraft.
Not saying that it can’t happen, but that’s not the biggest concern. In worst case I rather overrun the end of the runway at 20/30 kts than crashing short of the threshold.

Edit: I’m not adding « couple of knots »on some aircraft because I’m scared to stall but to have better control while flaring and to lower the pitch on old A319 with conf 3.

[Centaurus]

I've briefed many a new copilot on possible speed loss, when we get it they ask how did you know we'd get speed loss I answer experience and now you gained that too.

.Real story. 737-200 on dark night ILS to Runway 6L Guam Agana in the Marianna Islands. Cloud base about 1500 ft There are two runways at Guam. 6L and 6R. 6L has ILS. 6R has no aids. We received Instructions from ATC to break right when visual for sidestep right to 6R. As mentioned, there were no aids on 6R, so once you break right from the localiser 6L, it is a matter of glide path judgement. A taxiway with holding point joins 6L and 6R at their landing thresholds and separates both runways by about 300 metres. On this occasion, a PANAM 747 was holding on the taxiway intending to depart 6L (10,000 ft long). At 4 miles on final and breaking clear of cloud, we announced side-stepping right to land 6R. ATC then clears the 747 for take off 6L. So far, so good. With no glide slope guidance available for 6R, and glide slope 6L unusable for 6R, we drifted lightly high as we crossed threshold 6R. Wind calm.

Without any warning, turbulence hit the 737 which rapidly banked 20 degrees left and right and sank like stone. At the same time a stunned co-pilot called "Christ! Bug minus 20." . As PF I firewalled the thrust levers and hauled back for a raw data go-around on instruments. Fortunately this may prevented what would have been an extremely heavy and uncontrolled touch-down. We went into cloud while on the go-around and were then radar vectored for an ILS and landed safely. ATC queried the reason for the go-around and was told by the PM "severe windshear."

In fact, it was not windshear as such; but break-away jet blast from the 747 still on the taxiway at 90 degrees to us. Despite being cleared to take off on 6L some three minutes earlier, he had delayed lining up for some unknown reason. He did not tell ATC. From the left seat on short final I was aware of a shape with flashing lights on the dark taxiway adjoining both runways but didn't twig it could have been the 747. We had then passed close behind him as we crossed the threshold of 6R just as he opened up to break-away power to taxi for 6L. His jet blast hit us just before we flared. What saved us was the fact we were slightly high on slope over 6R threshold.
. All the briefings in the world cannot cover the one-in-thousand unexpected speed loss.

[RAT 5]

Similar learning experience as F/O PF, well anticipated by one of the older more wizened brigade of captain as was more common in those days. LGW, high traffic flow, the common "expect late landing clearance" i.e. around 200' and B747 lined up & cleared to go. Old wizened LHS warned to beware of turbulence and speed fluctuations as the beast ahead rolled. Don't over control on thrust nor flt controls. Firm and decisive. He was correct. Rock & roll <200'.
A message to pass on whenever I could.
Off thread, but there was also another message passed on, learnt from an interesting upset report, of medium a/c passing behind a heavy at crz FL. They had the mandatory separation, but hit the rough wake and went to significant bank angle. Not nice at night. After my first encounter of similar scenario, whenever I was vectored to pass behind a crossing a/c, I always asked what type, and if close behind a heavy nudged up 100'. It could also hit you if further away and 1000' below; a bit like being in trail on NAT tracks.
Sorry for the drift.

[FlightDetent]

Originally Posted by pineteam

I’m not adding « couple of knots »on some aircraft because I’m scared to stall but to have better control while flaring and to lower the pitch on old A319 with conf 3.

My opinion is that it's psychosomatic, i.e. would only happen if the pilot believes so.

Your own picture:
(click open in new tab to expand)

The pitch decrease is 0,74 degrees. Yet at the second shot, the A/C is accelerating and V/S is 800 fpm, not 700 anymore.
- I would agree the pitch changed by 0,6 degree, with all other things equal, due to the speed increase of 3 knots as photographed.

However, the Vapp increment was 2 knots. Pin - objectively - you are targeting a pitch change of 0,4 degree
: "to have better control while flaring and to lower the pitch on old A319". Come on.

Still, I do trust your word it is better. My claim? It's your mind playing tricks, not the aerodynamics/mechanics. You may feel more confident, trust the machine better, and be relaxed. That IS the mindset for a nicely controlled and well-organized landing. Some guys just do not need to add the 2 knots to get there.

You can be one too. Do a test, stop adding those tiny bits for 2 months and see: did the landings get worse?

Or be slick: propose to your F/Os: "Do you think those 2 knots really make a difference in handling a 50t jet in seafront breeze? Is it not just the yellow Vls mark scaring the hell out of us and putting us on the far side of the stress-performance curve? Would you like to try this one landing without adding a thing?" And watch them master it regardless.

my 5c.

[Callsign Kilo]

My answer is 'why?'

If the headwind component is 10 knots or less.
If a specified maximum increment is stipulated by the QRH

In manual flight, people don't generally fly their selected speed anyway (it's more than likely faster) and in most cases the only answer to why they want to fly a 'few knots faster' is to achieve a smoother touchdown. All a load of twaddle that has crept into the operation over numerous years by people who think they know better.

[pineteam]

FlightDetent I understand what you say. On the picture I was PM and the FO wanted those 2 knots extra. Myself I also do that but usually 2 to 4 kts extra or whatever is required to lower the nose when it's sitting at 7/8 degrees pitch on A319 config 3. I do not do it all the time as like you said, I like to try different techniques. On the old A 321, The aircraft seems to respond better with those little extra. I'm really not afraid to fly close to VLS as I know it's still safe. I see some guys who do not add anything and fly at VLS +1/+2 and they manage it but I also saw some very interesting landings. Were they related to that? Maybe not. But from my experience, it seems it works better with that extra speed with my landing technique at least; I'm the kind of the guy who has the tendency to flare too much that not enough. So those extra knots are my best friends when I screw up and flare too much and float xD. I will accept the challenge and not add any speed to the VAPP for the next 2 months and let you know.