Well it all depends.

In most A320's, the fms and flight control computers calculate the speeds independently. When there's a difference, we're invariably heavier than we think we are, and thus the FMS wants to fly at a slower speed than is appropriate. In that case, I'll add another 2 or 3 kts to maintain the proper ref+5.

The reply to the query “… if I want to add a couple of knots to my approach speed” could be:-

‘What’s the correction to the landing distance?’

A numerical answer is an opportunity to debrief the risks in approach and landing, distance margins, accuracy of declared runway state, etc.

Not providing an answer leads to a wider discussion on balancing risks, particularly the combination of speed and touchdown position, and thereafter stopping distance, wet runway, and overruns.

https://www.skybrary.aero/bookshelf/books/900.pdf table 6, page 11

It's not a written procedure to add a few knots. I suppose it'd fall somewhere between airmanship and technique. I don't think an FAA inspector in the jumpseat would fault a crew for increasing Vapp when it's sitting right above Vls.

I've heard of one person (thankfully not at my airline) who uses ref+10 all the way to 50ft even in calm wind, all in the name of smoother touchdowns. That's something else entirely.

As per QRH, we are allowed to increase up to 15kt above VLS. It’s really up to you.
Everytime I increase the VAPP, I insert it in the Flightsmart landing data to have an accurate landing distance. Unless I operate on short runways ( which we don’t; the shortest one is about 2500 meters), I rather approach slightly too fast than too slow and ending on the backside of the power curve. My worst landings were most of the time due to lack of energy.

RAT, #10, Is the landing roll not effected more by ground speed at touchdown than approach speed in the air?
I do not believe that it is because of the multiple effects of the increased air distance.

The key point is the increase in air distance due to the change in approach speed compared with that assumed in original landing performance (at the same wind speed). The change in airspeed / ground speeds are relative, although V squared is important during rollout.

The increased airspeed effects both the flare time and distance, plus any float due to the higher speed than required for the weight. When compared with the expected performance, based on an idealised landing profile based on Vref, then the aircraft would be both faster and further down the runway at touchdown.

Conversely, to retain the same safety margin assumed in the calculated performance, then the aircraft has to shorten the flare time to achieve the same touchdown point, and lose more speed - a fatuous argument where the limit would require a no flare landing with instant speed reduction.

Therefore any unaccounted speed increase reduces the safety margin assumed in the baseline landing distance.

Note Appx 1, para h (2) on page 6, - re adding speed: AC 91-79A Change 1, ‘Mitigating the Risks of a Runway Overrun Upon Landing’ https://skybrary.aero/bookshelf/books/3606.pdf

And note para j (3), page 8, - re minimum acceptable safety margin.

Check Airman, #11, I don't think an FAA inspector in the jumpseat would fault a crew…

…providing they consider / adjust the landing performance; or … unless the aircraft stops in the overrun.

(JT, add FAA inspectors to the lawyers who can be found in the long grass at the end of the runway ;) )

I don't think it's paranoid behaviour at all. When I see Vapp sitting just above Vls, the airplane is telling me that the assumed weights are wrong.

Will we die if the adjustment isn't made? Probably not, but unless we're going to a short runway, I don't see the harm in flying the speed the airplane thinks I should be flying, as opposed to the speed the load agent thinks is appropriate.

Standing by to be corrected if my understanding of the Vls/Vapp determination is incorrect.