For almost all of these, assistance must be turned off. I've found that sometimes the settings reset itself, and assistance was turned back on. At the beginning of any achievement flight, make sure assistance is turned off!

Also as a forewarning, many achievements seem to be bugged, or incredibly finicky to unlock, so I'd advise waiting until a patch is released fixing them before spending a lot of your time hunting the unachievable.

These achievements are usually pretty easy or don't take very long to complete, so this guide will cover them first.

Short Stuff

Land on a runway shorter than 2,000 feet, without using any assistance or bypassing any travel.

This achievement can be completed at any runway that is shorter than 2,000 feet, which can be viewed on the world map when selecting an airport. One such airport is the Juancho E. Yrausquin Airport (ICAO: TNCS) on the island of Saba, being the shortest commercial runway in the world at 1,312 ft.


By the Book

Request landing clearance from ATC at a towered airport, without using ATC assistance.


Despite having the same text as Start Me Up, this achievement does not require you to start the A320neo's engines, but instead requires you to request landing clearance from ATC at a towered airport. This can be easily achieved, pick a small regional airport (for example Hawthorne (KHHR)) nearby a major airport (say, KLAX), and take off from there, with the major airport set to your destination. Once you are close to the major airport, you will be given the option to request landing clearance.


Working for the Weekend

Complete a weekly activity.


To unlock this achievement, click on the top right box at the main menu, titled "Current Live Event". Complete this and you will unlock the achievement.


Mother Nature

Adjust the weather during a flight.


Open up the world map and set your destination as any airport, and leave the departure blank. When you load in, bring your mouse to the top toolbar, select weather, and change any variable.


Challenge Accepted

Complete any activity.


This achievement should be unlocked with the completion of Working for the Weekend, but if not, select "Activities" at the main menu, and complete any of them


Light Chop

Land at an airport where windspeeds are in excess of 5 knots, without using any assistance.

If you somehow have not got this achievement yet, any of the wind landing challenges will grant it to you, or you can edit your weather midflight to increase windspeed. It is advantageous to bump the windspeed up to 15 knots so you complete A Few Bumps at the same time.


Deadstick Landing

After receiving landing clearance, switch off engines and successfully land on the runway.


In the same way that you received landing clearance while completing By the Books, after receiving it, get relatively close to the runway, and shut off the engines. The method of doing this is different for every plane, but if you check around the cockpit or the checklists it should be easy to find. On the Cessna 172, the key on the bottom left turns off the engines. With the engines off, land on the runway.


Start Me Up

Manually start the Airbus A320neo's engines, without using Assistance.


Load into any airport with the A320neo, ensuring that you are starting at a gate or a ramp, so that you start cold and dark. Once loaded in, open the checklist from the toolbar at the top and follow it to start the engines.


A Few Bumps

Land at an airport where windspeeds are in excess of 15 knots, without using any assistance.

In the same way you completed Light Chop, set any airport's runway as your destination and load in, and then set the wind speed to over 15 knots in the weather tool, found in the toolbar at the top of the screen.


Stay on Target

Use the Instrument Landing System (ILS) to complete a landing.


I found it difficult to get the A320neo to not die on the way in if I spawned in flying, so I spawned at an airport, took off, and flew to a large airport with ILS capabilites. Give yourself a good distance from the runway you're landing at so you have time to fiddle with the AP. SkyVector[skyvector.com] has all the charts for most airports in the US for free, so use those to see the ILS frequency you have to tune into your plane. The frequency is tuned in at the center console's radio screens.


Uphill Climb

Land on a runway that has at least a 12 degree incline, without using any assistance.


This achievement, as well as On the Green, can be unlocked by completing the Bugalaga landing challenge. I found it not to register unless my plane rolled onto the steep slope at the end of the airstrip, so go easy on the brakes.


On the Green

Land on a grass runway, without using any assistance.


This is something of a sister achievement to Uphill Climb, easily achievable by completing the Bugalaga landing challenge.


Rubberneck

Use the Smart Cam to view a star landmark for 3 seconds, from a distance of 550 yards or less.

Get yourself into a slower GA aircraft, like the Cessna 152, or a bush plane, and take off from an airport near a star landmark. One example of this is the Space Needle in Seattle. Take off from Boeing Field (KBFI)'s 32R or 32L runways, and head towards heading 340. 6 or so miles from takeoff you'll see the space needle. Get close, and activate your smart cam key (s by default) until you unlock it.


Service with a Smile

Request each type of pre-flight Ground Service while at an appropriate airport gate.


Load up the A320neo at Innsbruck (LOWI) at a ramp, and power up the batteries (theyre on the panel above your head), and then contact Innsbruck Ground, and request all services, including ramp connection. Make sure to use the fuel tool in the toolbar to edit your fuel load in any way once the truck arrives to unlock Fill 'er Up!. After they're all connected and done their job, load into a gate at a major airport, power up the batteries, and request that the jetway connects with your aircraft, you should then unlock the achievement.


Fill 'er Up!

Refuel at any ground fuel station.


Load into any airport at the fuel box, and change your fuel load via the toolbar at the top.


In the Wild

Use the Smart Cam to view animals for 3 seconds, from a distance of 550 yards or less.


Go into the world map and search for "Fauna". Select one of the animals, pick a slow plane, and enable the smart cam (s by default), when within range. I'm hearing reports that this achievement is bugged, so maybe hold off before spending too much time on it.

These achievements are either difficult or take a while to complete.

Wheels Up, Wheels Down

Complete a non-stop flight of at least 300 miles from take-off to landing.


This one definitely leans on the time-based side. Just start any journey that it 300 miles long without stopping. Make sure to take off and land, no skipping!


Greased

Complete every Landing Challenge.


This one is gonna take a while, complete all landing challenges.


World Traveler

Land successfully at 500 different airports.


This one requires as it says, just land at 500 different airports.


Jack of All Planes

Complete a 300+ mile flight with every aircraft in the standard edition of Flight Simulator.


Wheels Up, Wheels Down, but for everything. Quite the feat.
This achievement is reported to be bugged, and as of 8/31/2020, cannot be achieved.


Tour Guide

Use the Smart Cam to view 25 star landmarks, from a distance of 550 yards or less.


Just like Rubberneck, but 25 times. Get to sightseeing!


Landmarks the Spot

Use the Smart Cam to view 100 star landmarks, from a distance of 550 yards or less.


Just like Rubberneck, but 100 times. Get to sightseeing!


SIDs and STARs

Land at every star airport shown on the World Map.


Quite simply, land at every map marked on the World Map as stars.


Completionist

Complete every activity


Complete every landing challenge, bush trip, etc. Gonna take a while.
This achievement is reported to be bugged, and as of 8/31/2020, cannot be achieved.


Goldrush

Complete the Nevada Bush Trip, without using any navigation assistance.


With all navigational assistance turned off, complete the entire Nevada Bush Trip.


Fire and Ice

Complete the Patagonia Bush Trip, without using any navigation assistance.


With all navigational assistance turned off, complete the entire Patagonia Bush Trip.


Anemoi

Complete the Anemoi Bush Trip, without using any navigation assistance.


With all navigational assistance turned off, complete the entire Anemoi Bush Trip.


My Way

Complete a non-stop 300+ mile flight from parking to parking spot, without assistance.


Easily achievable with Wheels Up, Wheels Down, aswell as a multitude of other achievements. Make sure to start at the ramp/gate, NOT the runway.


Job Shadowing

Create a flight plan based on a Live Traffic aircraft, then fly the route without assistance.


With real traffic turned ON, zoom in onto the world map until you can see planes. Click on one and click "Create Plan", now, with assistance turned off, fly out the plan.


Saddle Sore

Complete a flight of at least 8 hours with a propeller or turbo-prop aircraft.


Using one of these planes, fly an 8 hour long flight. You can of course, as you must, stop for fuel, but other you mustn't exit the flight.
This achievement is reported to be bugged, and as of 8/31/2020, cannot be achieved.


Frequent Flyer Miles

Fly from LFBD airport near Asobo Studio to KSEA airport near Microsoft HQ.


From what I've heard, skipping time invalidates this achievement, so get ready to leave the game running. Pick a long range plane, in the standard edition the 747-800 is best. Put in minimal weight via cargo and passengers, and load up with fuel. Make a flight plan from LFBD to KSEA and do it, let autopilot guide the way!

These achievements you'll likely get over time playing, and to brute force them would be far too strenuous or pointless.

Look Ma, No Hands!

Utilize autopilot for a total of 600 miles.


This one you should easily get through normal play as it means cumulative time, not in a single session or flight.


Back-Up Plan

Utilize pre-flight Pushback Service to move aircraft, for a total distance of 1 mile.


You could hypothetically increase the simulation speed and just have push-back push you back over a couple of minutes. If you don't want to bother, it'll naturally happen over time through normal play.


Road Trip

Taxi aircraft for a total distance of 100 miles.


This one is also easily done over play time, but as with Back-Up Plan, you can brute force it through time acceleration.


Pilot Program

Accumulate 50 hours of flight time in a single pilot profile.


No way to force this one either, just fly for 50 hours.


Century Club

Accumulate 100 hours of flight time in a single pilot profile.


This achievement will also come naturally, no way to force this one that I am aware of.


Journeyman

Accumulate 500 hours of flight time in a single pilot profile.


As with Century Club, this achievement will come with time.


Wing Commander

Accumulate 1000 hours of flight time in a single pilot profile.


As with Journeyman, this achievement will come with time.


Decathlon

Complete 10 weekly activities.


Make sure to stay on top of it and complete the challenges to get this one over with. No way to rush it I'm afraid.


Instrumental

Accumulate 50 hours of IFR flight time, including at least one take-off and landing.


When starting a flight in the World Map, select IFR (under your plane's icon), either low or high altitude depending on your aircraft. Complete these routes for 50 hours and you'll get it.


Night Owl

Accumulate 50 hours of flight time at night.


Either during night time live, or via you setting it to night through the weather tool, fly 50 hours at night time.


Flights of Fancy

Complete flights of at least 300 miles using a prop, jet and airliner.


This one won't take too long, just do a couple medium distance flights using each of these 3 types of aircraft.


Hydroplaning

Accumulate 50 hours of flight time in rainy weather.


Either during rain on live weather, or via you setting it to rain through the weather tool, fly 50 hours in the rain.