Frame drop at 250m height

[Hunony]

i just builded a flying car and when i got it to around 250 meters my game started to lag hard, i was playing around 35 fps then it got to 10

my mods are:

USITools

ToolbarControl

Airplane Plus

AmbientLight Adjustment

B9PartSwitch

BetterBurn time

BetterTimeWarp

Bluedog_DB

ClickTroughBlocker

Community Category Kit

Community resource pack

Contares

Contares_NAM

Contract Configurator

Contract Packs

Cormorant Aeronology

Decoupler Shroud

DMagicScienceAnimate

F9demo

Firespitter

FShangarExtender

KerbalEngineer

KerbalFoundries

KerbalReusabilityExpansion

KSPWheel

KWRocketry

Launchers Pack

Luna Multiplayer

Hyper Edit

Procedural Parts

Real Plume

Real Scale Boosters

Repo Soft tech

Retractable lifting surface

Smoke Screen

Tantares

TantaresLV

Trajectories

TransferWindowPlanner

TweakScale

UmbraSpace Industries

[xXKSP_playerXx]

What are your computers specs?

Because it could be problem with the graphics.

[Mark Kerbin]

Honestly. No clue. Check the console (F12)

Also a output log would be helpful. That can be found by following instructions on the pinned threads.