Intro
Landing an airplane using visual cues involves knowing how the sight picture ought to look and which adjustments to make to get it consistently on target. When landing the CRJ200, it’s important to know exactly when we need to start flaring to have consistent landings.
Digging in
The CRJ200 ACAPS document from Bombardier gives us a few useful pieces of information. Page 4 tells us the wheelbase is 37’5,” and a later sketch tells us about the pilot’s eye position and lookdown angle:
Note the warning about using it for approach visibility. That is likely due to the different deck angle on final. To derive the sight picture on final, we need to determine the distances between the wheels and our eyeballs for a variety of pitch settings. From the above drawing, we can back out our eyeball position as 1’11” behind the nose wheel. That means our lateral eyeball-to-mains distance is 35’6.” Pythagoras gives us a diagonal distance of 36.6 feet, and some trig gives us atan (8.92/35.5)=14.1 degrees:
Using these relationships, we can derive lookdown angles and distances at any desired pitch angles to figure out where we need to look. At this point, we can follow the same calculations we made for the E175, accounting for the different approach pitch of -2.5 degrees in the CRJ200:
When we look at the big spreadsheet of numbers for a 750-FPM VS at 141 knots ground speed, and a baseline flare height of 25 feet, we get the following table:
At a baseline 141 knots and 25-foot flare height, we end up on the back of stripe 5.
Our base case puts us on the back of stripe 5 if we execute perfectly. If we’re in an empty airplane with a ref speed in the low 120s, then we ought to flare closer to 20 feet to adjust for load factor. In other words, wait for the end of stripe 2 to start flaring.
Conclusions
Knowing when to flare helps us get more consistently precise landings inside the touchdown zone. The CRJ200’s geometry makes the sight picture different, so using visual cues reinforces what we’re looking for as we adjust.