How to Fly an ILS Approach in a 737

Disclaimer

Before continuing, you should know that this tutorial is an extension of my previous tutorial: How Realistically Descend Using VNAV. This is not merely a repeat of the user guide because these are aircraft-specific procedures and gives different procedures for different approach situations that the user guide does not include.


A Delta 737-800 touches down at Atlanta, likely after flying an ILS approach.

Straight-in

15 nm away from LOC intercept, idle throttle and set speed to 190 kts. Extend the flaps passing through 210 kts. 5 nm from LOC intercept set flaps 5 and 170 kts. When the G/S indicator dot appears (“glideslope alive”), gear down, set flaps 15 and 155 kts. Intercepting the G/S set flaps 30/40 and 135-145 kts (not corresponding).

Straight-in (low drag/delayed flaps)

10 nm away from LOC intercept idle throttle and set speed to 190 kts. Extend the flaps passing through 210 kts. G/S alive, set flaps 5 and 170 kts. Intercepting the G/S, gear down, set flaps 15 and 155 kts. Passing 1500 ft or 5 nm, whichever comes first (dependent of G/S angle), set flaps 30/40 and 135-145 kts (not corresponding).

“U-turn” type approaches

NOTE: There seems to be various procedures to this approaches, so I have picked the one that make the most sense to follow my previous tutorial.

Standard

On downwind, set speed to 210 kts. Turning base, set flaps 1 and 190 kts. Turning final, set flaps 5 and 170 kts. G/S alive, gear down, set flaps 15 and 155 kts. Intercepting the G/S, set flaps 30/40 and 135-145 kts (not corresponding).

Standard (low drag/delayed flaps)

Turning base, set speed to 210 kts. Approaching LOC intercept, set flaps 1 and 190 kts. G/S alive, set flaps 5 and 170 kts. Intercepting the G/S, gear down, set flaps 15 and 155 kts. Passing 1500 ft or 5 nm, whichever comes first, set flaps 30/40 and 135-145 kts (not corresponding).

Short final

If flying a shorter final approach, you will intercept the G/S at a lower altitude— possibly 1500 ft, and will have little time between LOC intercept and G/S intercept. On downwind, set speed to 210 kts. Approaching base/U-turn, set flaps 1 and 190 kts. Turning base, set flaps 5 and 170 kts. Midway through base or U-turn, gear down, set flaps 15 and 155 kts. Intercepting the G/S, set flaps 30/40 and 135-145 kts (not corresponding.)

I have observed this approach to KSNA, which approach path I live under. While I cannot tell the flap setting, the gear is often dropped during the U-turn, which means that it would have to be 5 and then 15. The rest is based on the previous approaches in this tutorial and whatever I could find on aviation forums.

Note

The most common flap setting for landing is flaps 30, but flaps 40 is used for short runways, heavy loads, etc. Landing speeds at flaps 30 are usually around 140 kts and 130 kts for flaps 40. This is a rough estimate— speeds can vary and there are many factors. If heavy, add 10 kts to all intermediate speeds, and if light, subtract 5 at the most.

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This will be very helpful to other pilots, thanks for making this!

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