Hey everyone! I’ve recently started taking my flight simming more seriously and I'm trying to learn the "proper" way to fly. But man, the amount of formulas is crazy. Wind correction, top of descent, fuel burn, true airspeed... my desk is covered in notes.

For those of you who fly high-fidelity stuff (A320, 737 or even GA), do you actually sit there and calculate everything manually? Or do you just rely on the FMC and some "rules of thumb"?

I want to keep it realistic, but I feel more like a math student than a pilot right now. What are the essential formulas that you actually use in every flight, and what can I leave for the "nerds"? Thanks!

4 hours ago, SvyatoslavMohov said:

Hey everyone! I’ve recently started taking my flight simming more seriously and I'm trying to learn the "proper" way to fly. But man, the amount of formulas is crazy. Wind correction, top of descent, fuel burn, true airspeed... my desk is covered in notes.

For those of you who fly high-fidelity stuff (A320, 737 or even GA), do you actually sit there and calculate everything manually? Or do you just rely on the FMC and some "rules of thumb"?

I want to keep it realistic, but I feel more like a math student than a pilot right now. What are the essential formulas that you actually use in every flight, and what can I leave for the "nerds"? Thanks!

Hi there,

 

If you fly with steam gauges, you need to be mostly aware of when to start your descent, your rate of descent, and correct timing between points based on GS. Wind correction: just an idea. The wind data you use in the calculation will differ due to constant changes, and the wind aloft is just a plain forecast during your preflight. Yes, today the FD winds are quite accurate due to the many ways they collect data. Also, when flying, steam gauges, it is important to have a printout of your planned route and to periodically check and keep score at set intervals to identify any trends, such as fuel, time, temperatures, winds, tas, etc. These factors will show whether you are on target, ahead, or behind. 

FMS-equipped, based on SOPs, you will find a variety of procedures. What is common is just one FPL as a reference, and God knows what the training departments can come out as procedural. Some airlines are easy; others, despite the technology, prefer to keep pilots busy buried in paperwork to cover their insecurity behind the training department desks. I'd just like to sign the master FPL, toss it in the envelope, and let the computer do its job. Such a beautiful day up there in paradise. 

37 minutes ago, LRBS said:

Hi there,

 

If you fly with steam gauges, you need to be mostly aware of when to start your descent, your rate of descent, and correct timing between points based on GS. Wind correction: just an idea. The wind data you use in the calculation will differ due to constant changes, and the wind aloft is just a plain forecast during your preflight. Yes, today the FD winds are quite accurate due to the many ways they collect data. Also, when flying, steam gauges, it is important to have a printout of your planned route and to periodically check and keep score at set intervals to identify any trends, such as fuel, time, temperatures, winds, tas, etc. These factors will show whether you are on target, ahead, or behind. 

FMS-equipped, based on SOPs, you will find a variety of procedures. What is common is just one FPL as a reference, and God knows what the training departments can come out as procedural. Some airlines are easy; others, despite the technology, prefer to keep pilots busy buried in paperwork to cover their insecurity behind the training department desks. I'd just like to sign the master FPL, toss it in the envelope, and let the computer do its job. Such a beautiful day up there in paradise. 

 I was probably more interested in the question of whether you remember all the formulas that you studied as a student and whether you actively use them.

4 hours ago, SvyatoslavMohov said:

 I was probably more interested in the question of whether you remember all the formulas that you studied as a student and whether you actively use them.

The 3:1 rule is most commonly used in steam gauges to calculate TOD or loose altitude. If you need to be at 10K/250, add 10 NM to allow time to slow down. 

You cruise at 330 FL, and the airport is  0 FT elevation, start at 110 NM + 10 NM to give you enough time to slow down to 250 kts @ 10K and continue from there. 

If the airport is at 3,000 ft elevation, you need to lose 30,000 ft, so TOD is at 90 NM + 10 NM to slow down. That + 10 NM may vary based on the aircraft's inertia, a good number to start.

Now, as to ROD (RATE OF DESCEND), there are two ways to skin the cat, but all have in common watching your ground speed constantly and calculating:

a) ground speed x 5= fpm 300 kts x 5=1500

b) ground speed : 2 = fpm 300 kts : 2= 1500

600 KTS GS ROD 3,000 FPM, you get the idea.

 

I'm mentioning GS because of the winds; you need to watch that.

 

This is what is used more as mental gymnastics; all the other stuff is...As I mentioned, periodically check and keep score at set intervals to identify any trends, such as fuel, time, temperature, wind, TAS, etc., against the FPL. 

 

FMSs are a blessing in our days.

Edited April 11Apr 11 by LRBS

Yep, the 3:1 rule is one to remember. Another one is the 2% rule for ground speed: if you know your true airspeed, the corresponding ground speed increases by 2% for each 1000 ft of altitude. For everything else I use Simbrief or an EFB calculator. I do remember the equations, but mostly because I used to do that (I use a lot of math in my job). 

9 hours ago, SvyatoslavMohov said:

I want to keep it realistic, but I feel more like a math student than a pilot right now. What are the essential formulas that you actually use in every flight, and what can I leave for the "nerds"? Thanks!

For the most part you do, but it's mostly wags and techniques. Here are some common ones I use every flight.

1. Mach for miles per minute: Let's say you are doing Mach 0.70. That's 7 miles a minute. This technique helps you cross verify crossing restrictions and if you can make it. Scenario, ATC says, descend and maintain 10,000, cross 20 miles South of VUZ at 15,000. We are currently at FL340 80 miles from VUZ. That puts you 60 miles from the restriction and 19,000 to lose. So, 7 miles a minute takes you about 8.5 minutes to get there. 19,000 feet requires about 2200 feet per minute. So roughly 2500 feet per minute should be doable. Knowing what your aircraft can do will tell you if you are good for the restriction or not. Most can get away with 2500 feet per minute from that altitude with no problem. 
2. 4 times your altitude to lose: Say you are looking at the final approach fix and it's at 2000 feet. Again, you are at FL340. That's 32,000 to lose. 4 x 32 is 128 miles to get down. You want to put that descent request in no later than 135 miles from that FAF. Notice I use 4 instead of the standard 3. I use 4 to account for slowing to 250 before going below 10,000.
3. 12 at 12 or 13 at 13: This is a good rule of thumb for slowing to 250 by 10,000 feet. 12 at 12 = 1200 feet per minute at 12,000 feet and 13 at 13 = 1300 feet per minute at 13,000 feet. It can be plus or minus depending on weight, but usually gets me right at 250 at 10,000. Works great for any aircraft, to include the slippery G550. I picked it up while flying DC10s. 

These work pretty well for me and I use them each flight. Yes, the FMS/FMC does this for you, but it's also good to know to back it up or in case it fails. You can actually do a vertical direct to altitude and it will tell you what VVI is needed at that point. But hey, old habits die hard.    

Don't be drawn into thinking you have to Einstein to be a pilot.

Yes, you learn a lot of stuff to pass theory exams, but as other practising pilots have replied, it is mostly "rules of thumb" that get you by in day-to-day flying, and a fair serving of common sense.

Few years ago - I was in similar boat and many people who had no aviation background whatsoever kept on telling me that you need be mathematician to become a pilot. As of now few years later & as a proud holder of UK CPL with ME IR and some 850+ hours of flying (MEPs and Turboprops) - I can positively say that's not the case. All you need is cool head, Good hands to eye co-ordination and be effective team player. These days everything is done digitally either on EFB or tablet - From mass and balance to performance calculations. Even those ones you can do it yourself and certainly aren't difficult and generally straightforward, there are various guides and examples that you can follow in Aircraft flight manuals. There are no complex formulae or equations that pilots have to remember to carry out their day to day tasks.  We instead use various rule of thumb (E.G 3 in 1 rule, 5 x Groundspeed for V/S.etc) nothing too complicated, Once you do it more often and have suitable experience - this becomes like second nature. I myself do not have either science or maths background but I did study those subjects up to High school level. As long as you can do basic addition/subtraction/multiplication - there should not be a problem at all. 

The only time you will have to remember complex formulae and equations is when you are undertaking theory exams - I did UK CAA ATPL exams and these are considered to be most intense and detailed. During those exams I had to remember various formulae and equations so that I could answer the questions correctly. Fortunately once you have passed those exams - you can close that chapter as you will never see or use those equations ever again in your professional life. 

Edited April 13Apr 13 by CAP1234

Thank you for your answers, they will help me a lot!

22 hours ago, CAP1234 said:

Once you have passed those exams - you can close that chapter as you will never see or use those equations ever again in your professional life. 

1000% correct!