You can see that FPLN file is bigger, because the gauge ovewrite with SID/STAR/Approach waypoints, and the CSV file is the FMC data
"Aircraft Ident","Airbus","A320"
"Save Flight Plan","1."
"Departure Aircraft Position","1.","28L"
"Flight Plan File",,"C:\\Documents and Settings\\Fdd\\Mes documents\\Fichiers Flight Simulator X\\IFR Monterey Peninsula to Charles M Schulz - Sonoma Co.PLN"
"Departure Airport : ","KMRY"
"Departure Airport Elevation : ","257."
"Departure ICAO region : ","K2"
"Departure Position : ","28L"
"Destination Airport : ","KSTS"
"Arrival Airport Elevation : ","125."
"Destination ICAO region : ","K2"
"Trip total Distance : ","132.23"
"Distance Remaining : ","63.461"
"Altitude Descent Target : ","6000."
"Descent Target distance : ","0."
"Current Flight settings : "
"Optimal Flight Level : ","172."
"FMS enabled : ","1."
"FMS init OK : ","1."
"FMS TakeOff Init OK :","0."
"Current flight phase :"
"Aircraft takeoff state","1.","0=Takeoff is not completed : SFCC in Ground mode 1=had takeoff : SFCC in flight mode"
"Takeoff phase","5.","-1=not cleared 0=Ready 1=takoff go 2=Aircraft is airbone 3=THR RED ALT reached 4=Initial acceleration 5=Aircrat is above 10000ft. Takeoff is completed"
"Aircraft Climb","0."
"Aircraft Climb phase","4.","0=aircraft is below 10000ft 1=Climb acceleration 2=Aircraft climb 3=Climb is completed 4=descent is engaged"
"Aircraft cruise","0."
"Aircraft descent","1."
"Aircraft Descent phase","4.","1=initial descent engaged 2=aicraft is above conjunction altitude 3=aircraft is between Conjunction altitude and 18000ft 4=aircraft is below 18000ft"
"Aircraft Approach phase","0."
"Callout 80kts : ","1."
"Callout V1 : ","1."
"Callout Vr : ","1."
"Callout V2 : ","1."
"Callout Check Speed : ","0."
"FMS SETUP : "
"TakeOFF Page : "
"Runway Takeoff : ","28L"
"Takeoff V1 Vr V2 : ","119.","134.","141."
"SRS Speed : ","156."
"GPS Nav Flag : ","1."
"Takeoff Runway Ok : ","1.","28L"
"Cost Index Value : ","1.","40."
"Takeoff THUST mode 1=TOGA 2=FLEX : ","2."
"Flex To Temp setting : ","1.","38."
"Takeoff Flaps Config : ","3.","0=clean 1=Slats1 2=1+F 3=1+2 4=3 4=full"
"Takeoff Heading : ","0.","278."
"LNAV Engage Altitude : ","1.","0."
"Thrust Reduction Altitude : ","1.","1700."
"Acceleration Altitude : ","1.","1700."
"Econ Thrust : ","1."
"EXPEDITE : ","0."
"N1 climb Thrust Below FL100 : ","1.","83.212"
"Climb Speed below FL100 : ","1.","250."
"Climb Speed Green Dot : ","0.","0."
"Constraint Altitude : ","0.","0."
"Constraint Speed : ","0.","0."
"QNH Transition : ","1.","18000"
"QNH State : ","0.","0=barometric value 1=STD"
"CLIMB Page : "
"Climb Thrust ECON : ","1."
"N1 Climb Thrust above FL100 : ","1.","82.612"
"Climb Econ Thrust : ","1."
"Climb Thrust Expedite : ","0."
"ECON Flight Level : ","1."
"Flight Level 1 : ","1.","130."
"Climb speed IAS value above FL100 : ","1.","350."
"Climb Speed Econ : ","1."
"Conjunction IAS/MACH Altitude : ","1.","29000"
"Climb Speed MACH Value above Conjunction Alt : ","0.","0."
"Climb Speed MACH Econ : ","0."
"CRUISE Page : "
"Cruise ECON Speed IAS : ","1."
"Cruise Speed IAS FL1 : ","1.","350."
"Cruise ECON Speed MACH : ","0."
"Cruise Speed MACH FL1 : ","0.","0."
"Change Flight Level : ","0."
"Flight Level 2 : ","0.","0."
"Weight Flight Level 2 Kg and Pounds : ","0.","0.","0."
"Cruise Speed FL 2 Mach : ","0.","0."
"Top Of Descent : ","1.","0."
"Descent Constraint : ","0."
"FCU Settings : Knob FCU 0=selected mode 1=managed mode "
"SPEED : ","1."
"HDG : ","1."
"ALT : ","1."
"Altitude Constraint : ","0."
"Autopilot Pitch mode : ","1."
"V/S mode : ","1."," 0=Selected 1=managed"
"Speed Managed IAS : ","300."
"Speed Managed Mach : ","64.231"
"Aicraft is Above Transition : ","0."
"user FCU altitude Flag : ","0."
"ILS Land Phase : ","0."
"ILS Mode Armed : ","0."
"Approach Mode Armed : ","0."
"Localizer Armed : ","0."
"Approach type : ","1."
"Landing : ","0."
"Flare : ","0."
"Roll Out : ","0."
"Number of Waypoints : ","12."
"Offset waypoint list : ","0."
"Engine 1 Generator : ","1."
"Engine 2 Generator : ","1."
"DC Volts Selector : ","0."
"Inertial Sys on/off : ","0."
"Inertial Data : ","0."
"Panel Cabin Light : ","0."
"Engine 1 Bleed : ","0."
"Engine 2 Bleed : ","0."
"APU Bleed : ","0."
"VOR Switch 1 : ","1."
"VOR Switch 2 : ","1."
"Index of Active Waypoint : ","5."
"Checklist ID : ","13."
"Aircraft is above Mach Altitude MACH mode is engaged : ","0."
"Speed/MACH button pushed : ","0."
"User specific landing frequency : ","0."
"FSX landing frequency : ","109.3"
"SFCC flag Flaps on ground : ","0."
"SFCC : Aircraft is airborne : ","1."
"SFCC Flaps config before takeoff : Aircraft is on ground : ","0."
"Zero Fuel Weight ZFW : ","54437"
"No Smoking Switch State : ","1."
"Seat Belt Switch State : ","1."
"Engine 1 Fuel burned since departure in Pounds : ","1216."
"Engine 2 Fuel burned since departure in Pounds : ","1226.1"
"Index first approche waypoint if Go Around : ","0."
"Altitude first approach waypoint if Go Around : ","0."
"Speed first approach waypoint if Go Around : ","0."
"Autopilot engaged : ","1."
"AutoThrottle engaged : ","1."
"Autopilot Hold Altitude : ","6000."
"Autopilot Altitude Lock : ","0."
"Autopilot heading value : ","278."
"Autopilot Heading Lock : ","0."
"Autopilot GPS Drives NAV1 : ","1."
"Autopilot Nav Lock : ","1."
"Autopilot AirSpeed Hold mode : ","0."
"Autopilot Mach Hold mode : ","0."
"FPA mode engaged : ","0."
"FPA Value in degrees : ","0."
"Final Approach Altitude unlocked : ","0."
"User descent Altitude Target Flag","0."
"User descent Altitude Target value","0."
"User Descent Altitude Target Ok","0."
"Arrival Altitude without STAR","3100."
"Hydraulic Green","1."
"Hydraulic Yellow","1."
"Hydraulic Blue","1."
"Fuel On Board at Departure in Pounds","18860"
"Aircraft is changing FL Cruise ","0."
"Approach Gradient User Value","-3."
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"Reserved","Not used on this version"
"SID Loaded : ","1."
"SID data : "
"28L"
"MUNSO 2.OSI"
"278."
"500."
"1700."
"1700."
"6000."
"0."
"0."
"3."
"1.","W","K2",,"HEKIV","0.","0."
"2.","W","K2",,"UBOBY","0.","0."
"3.","V","K2",,"OSI","0.","0."
"STAR Loaded : ","1."
"STAR data : "
"32-14-01"
"PYE Transition"
"ILS/LOC/RNAV/VOR-32 RNAV/VOR-14 RNAV-01"
"1."
"1.","V","K2",,"PYE",,,,"6000",,"0",,,,
"Waypoint has an Holding pattern : ","0."
"Holding Pattern Armed or engaged : ","0."
"Hold pattern is running : ","0."
"Index WPT STAR holding pattern : ","1."
"WPT STAR holding pattern completed : ","0."
"Turn Direction 0=No current turn 1=Left 2=Right : ","0."
"Initial Heading : ","0."
"Opposite leg : ","0."
"Hold Pattern timing : ","0."
"Hold Pattern position : -1=initialisation 0=first turn 1=opposite leg 2=turn back 3=come back init WPT : ","0."
"Waypoint has an DME ARC : ","0."
"Waypoint has a leg turn back (teardrop turn) : ","0."
"Approach Loaded : ","1."
"Approach Data : "
"Transition name : ","PYE"
"32"
"ILS"
"5."
"1","U",,,"PYE32","38.23993289","-122.7620887","3000","220","0",,,,
"2","W","K2",,"LUSEE",,,"3000","200","1","1","321","141","65"
"3","W","K2",,"EDOVE",,,"2700","180","0",,,,
"4","W","K2",,"PIGPN",,,"2000","0","0",,,,
"5","R","K2","KSTS","RW32",,,"255","0","0",,,,
"APPR Waypoint has an Holding pattern : ","0."
"Holding Pattern Armed or engaged : ","0."
"Hold pattern is active : ","0."
"Index APPR WPT holding pattern : ","0."
"WPT APPR holding pattern completed : ","0."
"Turn Direction 0=No current turn 1=Left 2=Right : ","0."
"Initial Heading : ","0."
"Opposite leg : ","0."
"Hold Pattern timing : ","0."
"Hold Pattern position : -1=initialisation 0=first turn 1=opposite leg 2=turn back 3=come back init WPT : ","0."
"Waypoint has an DME ARC : ","0."
"Waypoint has a leg turn back (teardrop turn) : ","0."
"FSX Variables monitoring Values : "
"AUTOPILOT CONFIGURATION"
"Autopilot Armed","1."
"Auto Throttle Armed","1."
"Autopilot AirSpeed Hold mode","0."
"Autopilot Airspeed KIAS Value","300."
"Autopilot Mach Hold mode","0."
"Autopilot Mach Value","0.55"
"Autopilot Heading lock mode","0."
"Autopilot Heading Dir value","278."
"Autopilot NAV1 Lock","1."
"GPS Drives NAV1","1."
"Autopilot Altitude Hold","0."
"Autopilot Target Altitude","6000."
"Autopilot Vertical Speed ft/mn","0."
"Aircraft performances and environement"
"indicated Airspeed","327.48"
"Indicated MACH","0.60372"
"indicated Altitude","12926"
"Verticale Speed Ft/mn","-195.01"
"Total Weight in Kgs","61884"
"Fuel on Board in Kgs","7447.3"
"Flaps Position","0."
"Spoilers Armed","0."
"Ambiant Wind Velocity","6.9815"
"Ambiant Wind Direction","287."
"Ambiant temperature in Celsius","-2."
"A32x series FD-FMC Version beta 1.00 September 2015 - Data save file gauge v1.36 - CSV file format can be read with EXCEL or similar software"
"© François Dore - September 2015"
"LoggerX.dll Module © Robbie McElrath - LoggerX can be included in XMLTools.dll © Tom Aguilo"
"LoggerX Version : ","2."
Without this file, FMC cannot work when you reload your flight.
This file is also an excellent blackbox, if you have a bug, because I know the state of all aircraft systems. This file is very easy to read and you can find all information about your flight.