Engaging Approach and Autoland cause a drop of current vertical speed

[morphelianus]

MechJeb Version (DEV RELEASE)

2.10.0.0-1001

KSP Version

Stock 1.10.0.2917 de-de
Making History 1.10.0
Breaking Ground 1.5.0

Description

I recognized a short drop of the current vertical speed whenever I engaged aircraft approach and autoland after I engaged aircraft autopilot. Sometimes it could even drop into negative values. After a couple of seconds the current vertical speed matches again the target vertical speed and everything is fine.

Originally posted by @morphelianus in #1312 (comment)

Replication Case

I captured 2 videos.
1st video
Starting on KSC runway 27 with engaged SAS
Engaging autopilot with Altitude Hold of 2500 meters, Vertical Speed Hold of 10 m/s, Heading Hold of 90°, Bank Angle of 15°, Horizontal Speed Hold of 120 m/s
Engaging approach and autoland for Island runway 09 after reaching 1100 meters
-> Results in a drop of the current vertical speed to roughly -19 m/s
https://youtu.be/XpzgTOlX1SE

2nd video
Starting on KSC runway 27 with engaged SAS
Engaging autopilot with Altitude Hold of 2500 meters, Vertical Speed Hold of 10 m/s, Heading Hold of 90°, Bank Angle of 15°, Horizontal Speed Hold of 80 m/s to match Approch Speed
Engaging approach and autoland for Island runway 09 after reaching more than 1500 meters to be above glide slope
-> Results in a drop of the current vertical speed to roughly -25 m/s
https://youtu.be/fhlCGYUri1k

KSP.log

KSP.log