Your speed depends on wind, you may have had some headwind, also I would DEFINITELY recommend using VNAV, I used to not use it either, but when I did, it’s a game changer. If you don’t know how to use it I know that Infinite Flight has a useful tutorial on youtube
Your 266 kts are an indicated speed. And the M0.78 are a true air speed.
You put the finger on the most important thing to understand.
Indicated speed allows to pin a specific event to a unique indicated speed (like stall speed, rotate speed).
The density of air changes with temperature and altitude, so if you use true air speed you would have tables and tables to check to know what is such or such speed for such or such event. But if you use indicated speed, one event = one indicated speed whatever the temperature or altitude.
TAS ≈ IAS + 1% (per 600 ft) + 1% (per 5°C) TAS = True Air Speed, IAS = Indicated Air Speed Higher, hotter, faster
In the plane, you use IAS and the Mach TAS. Between 25000 (FL250) and 30000 ft (FL300) you switch to Mach speed, otherwise the plane would accelerate to the death (higher, hotter, faster). At this moment, you set Mach speed, so a TAS, so the IAS starts to decrease.
When descending, between 25000 (FL250) and 30000 ft (FL300) you go back to IAS.
The modern airliners change between IAS/Mach automatically.
And about the wind, it is simply add to IAS and TAS, and change your ground speed (the one that a car would display).
Under 10000 ft (FL100) it is not allowed to fly faster than 250 kts (IAS).
It’s not too slow, most narrowbody jetliners fly between their typical Mach .78 or 79. Other planes like the 777 can fly at Mach .84 if you’re looking at a realistic setting. Usually your TAS(True Air Speed) and GS(Ground Speed) shows how fast you really are going.
When I started using IF Online, I used to manually decend, but it can be a pain, therefore I started using VNAV. VNAV can be your best friend or it can be your enemy if handled mischievously. VNAV is best to be monitored when upon decent and to make sure you’re not 260kts or above under FL100(10,000 ft MSL)
Another thing: I recommend using Flightaware or a site that can formulate flight plans, so you can find the correct fixes,suggested altitudes, and even much more to enhance your flight experience.
(https://flightaware.com/) Simply just type in your departure airport and arrival. Once you find one, try to find one that’s closest to your real life timing(As timing can hinder in your Cruising Speeds, Headwind and Tailwind).
Also fly whenever you feel, just make sure you have the time and fuel for it!
Your 266kts IAS is a dynamic pressure reading. So it gets smaller as you fly higher because there is less air to exert pressure as the air impacts the aircraft at its actual speed, TAS (true airspeed). As mentioned the M number is TAS, but expressed as a percent of the speed of sound.
The dynamic pressure is what directly causes lift generation of the wing, that’s why IAS is used directly for flying speeds (and flap and gear max air stress speeds).
But the M number is about a high speed limit on lift generation: airflow choking around the wings near the speed of sound (the orderly flow of air is disrupted).
So at the upper altitudes of flight your TAS as given in mach can look very high compared to the pressure the thin air is exerting, the 266kt IAS.
To the extent your engines can take you even higher, you eventually would get into a situation where you are squeezed between the mach limit and stall speed - you are close to the speed of sound, yet there is not enough dynamic pressure to generated enough lift to fly!
Hello, welcome to the aviation community! To answer your first question, the 266kts is your airspeed. Your ground speed is likely much higher, 450kts+. As for your second question, you should use VNAV. You may not be using it wrong? Make sure to have an altitude set at a waypoint, and the VNAV will do the rest. Once the altitude and VS turn purple, just let the computer do the descending. If you need help setting altitudes, these videos were very helpful to me: Flight Planning - YouTubeVNAV Tutorial - YouTube
One of the longer flights you can do without pro is KSAN to KSFO, use a United 737-700 or Delta/AA A321.
See you in the skies!
I used to do before i got global back in like 2019, KLAX-KSFO but i used to use the whole border of the non pro zone, that would usually last an hour of flying. Sometimes i would do a loop in the FPL to make my flight last loinger