I'm trying to figure out how to compute the appropriate vref speeds for the Longitude. I've been looking at some youtube videos and they are all over the place. From110 to 160.

I've seen approaches with an AOA almost in the red, plane floating down the runway, bouncing up and down like an electric chicken before settling down. That all can be right. 

Here is a description of an approach and landing with the Latitude:

!For the landings on Eisenhower National’s Runway 19L it was full flaps and gear down at the final approach fix, with ATs set to an approach speed of 120 knots. I kicked off the autopilot and got to sample the roll and pitch forces in rowdy thermals. Every time airspeed is gained, the ATs come back; every time airspeed nods off, they power up. The main thing is that they nail airspeed unerringly. On short final, Wuertz selected our VREF of 96 knots and the ATs retarded some more. At 50 feet agl, they automatically disconnect and power goes to idle. A disembodied female voice calmly says “Autothrottle”—meaning the ATs are off and it’s all yours, buddy."

Source: https://www.aopa.org/news-and-media/all-news/2015/november/pilot/t_latitude

33 minutes ago, Ricardo41 said:

I've been looking at some youtube videos and they are all over the place. From110 to 160.

The problem is (assuming you're watching real-life landings), the vref speeds are dependent on weight. That's why there's such a variance. 

1 minute ago, mtr75 said:

The problem is (assuming you're watching real-life landings), the vref speeds are dependent on weight. That's why there's such a variance. 

no these are msfs videos

1 minute ago, Ricardo41 said:

no these are msfs videos

I would ask the people doing the videos where they got their power tables from. Or search for the Citation Longitude POH or AFM on the google machine. Though apparently it's hard to find. 

This provides some performance information:

https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/5628ecd03661764f8625850a00651dd7/%24FILE/T00015WI_Rev4.pdf

With flaps full and gear down, the autothottle (AT) flies 140KIAS and it will hold this speed until 50ft AGL, whereupon it retards the throttles for landing.  But, there are Vref and Vapp between 140KIAS and 50ft AGL, and 140KIAS is usually way too fast over the threshold.  How to tell the AT to forget about 140KIAS and instead fly Vref and Vapp?  All I've heard anyone say is "select Vref" or "select Vapp".  HOW???  What exactly is the procedure to "select" these speeds (I know how to generate them and select them in the FMS, thus sending them to the PFD) and -- most importantly -- have the AT fly them on approach?

Edited April 25, 20233 yr by ATP CFII MEI
Forgot to add some important supporting information.

I've been practicing these operations in the last week:

• Change SPD mode setting on AP from FMS to Manual.
• Dial in the Vapp speed - I set this up so that the aircraft is at Vapp at the FAP
• Unless there is a strong wind (or gusting crosswind, etc.), I lower this to Vref before disconnecting the AP

The AT will fly these set speeds and pull the power at 50 AGL.

On 9/26/2020 at 8:50 AM, Ricardo41 said:

I'm trying to figure out how to compute the appropriate vref speeds for the Longitude. I've been looking at some youtube videos and they are all over the place. From110 to 160.

I've seen approaches with an AOA almost in the red, plane floating down the runway, bouncing up and down like an electric chicken before settling down. That all can be right. 

Here is a description of an approach and landing with the Latitude:

!For the landings on Eisenhower National’s Runway 19L it was full flaps and gear down at the final approach fix, with ATs set to an approach speed of 120 knots. I kicked off the autopilot and got to sample the roll and pitch forces in rowdy thermals. Every time airspeed is gained, the ATs come back; every time airspeed nods off, they power up. The main thing is that they nail airspeed unerringly. On short final, Wuertz selected our VREF of 96 knots and the ATs retarded some more. At 50 feet agl, they automatically disconnect and power goes to idle. A disembodied female voice calmly says “Autothrottle”—meaning the ATs are off and it’s all yours, buddy."

Source: https://www.aopa.org/news-and-media/all-news/2015/november/pilot/t_latitude

96kts is way too slow look for around 125KTS approach speed and A/T off around 200 AGL

Edited October 18, 20241 yr by Flyfaster_MTN002

I set A/T of at approach and use manual speed according to the recommended approach speed and pull the power of at 50 AGL at 120-125kts depending on the wind situation.

I keep the A/T on, as it pulls power itself when passing 50' AGL (I pull my throttle lever also, so that I can use it to add reverse thrust if needed, but the A/T does pull power to idle on its own).

Once I depart the runway, I turn off the A/T in accordance with the checklist.