Apr 4, 2011, 11:42 AM
Post #1 of 9
Landing Pattern Factors
We don't have enough threads about landing patterns
Instead of rehashing those, I thought we could identify the factors, and work from there instead.
There are several things that used to be "common knowledge" that aren't so common any more; exit order and separation come to mind. Maybe we need to analyze and weight the considerations involved in landing patterns (note: I'm NOT an expert in landing patterns -- I'm from that past when all canopies were big and slow).
What are the things that impact landing patterns? (no order here, just what I can think of). In the long run, these ought to be weighted, and then the ones that only apply to some dz's should be identified, so they can be eliminated from the dz's that don't have them. We can also include in the long run which ones are most heavily correlated with incidents (no, we don't have much more than gut feel and the 10 or so fatalities here, but there are some pretty educated guts).
But for now, let's just list factors. I'm not including personality factors right now (e.g. "current poor landing discipline"). Please feel free to add, or to call me an idiot (within the personal-attack rules of dz.com, of course ).
Number of jumpers in the air at a time (usually a factor of A/C size) Different loads or groups integrating Different landing areas for high-performance landings Wide mix of canopies Active student operation (i.e. lots of video & instructors) Changeable winds Small landing area Poor or few outs Long skinny landing area Poor ground visual cues (i.e. the windsock sucks) Need to coordinate with air traffic Percentage of regulars vs. visitors Transportation back from outs
1) Number of aircraft flying. I separate this from number of jumpers because the number of aircraft flying could have a different impact than just the number of jumpers (could impact jump runs/spots, or if the planes are flying close enough together, the higher-loaded canopies from Airplane #2 could find themselves in the pattern with the lighter-loaded canopies from Airplane #1)
2) Number of students in the pattern. It's a sub-factor of your "active student operation" piece, but the reason I think it's a factor (though it may be what you call a "personality" factor) is the "pattern myopia" that's common among students; as much as we teach them and work with them to look before they turn and scan throughout the pattern, the reality is that students very often get into that singular focus on checkpoints and turn altitudes and successfully completing their own pattern, to the exclusion of all other visual "information" around them.
(This post was edited by NWFlyer on Apr 4, 2011, 12:15 PM)
This might be of significance when students are out first and are in the pattern when the video guy who was last out on a Velo loaded @ 2.5 has caught up with them and simply can't out-float a Navigator loaded @ 0.8
I think what you are implying is the very real issue of the interplay of the wind direction and a long skinny LZ.
If the long axis of the LZ is roughly parallel to the wind line... easy stuff for students and low timers. However, if the long axis of the LZ is across the wind line (roughly perpendicular), the students and low timers are far more likely to land someplace other than the LZ... that may be no problem, or may be a serious problem.
Of course, all jumpers are affected by this, but the students and low timers tend to have the most trouble.
Different opening altitudes Different freefall speed/duration (freefly vs RW vs wingsuits) Exit order Time between exits (not distance - time!)
These can all tie in together. I've been last out on wingsuit jumps, with a looong delay after the last tandem, had a long freefall, opened fairly high, spotted the tandems a long ways below me - and found myself overtaking the tandems in the pattern.
(This post was edited by BrianM on Apr 4, 2011, 8:01 PM)