Last week, all pilots and passengers miraculously survived a midair crash at Centennial Airport, near Denver, CO. A Cirrus SR22, which was flying a right traffic pattern to runway 17R, hit a Metroliner that was on a long final to runway 17L. The Cirrus, which was flying a shallow, continuous turn from downwind to final, hit the Metroliner slightly from behind and above the aircraft. The Cirrus lost it's nose landing gear as it passed through the top of the Metroliner. The Metroliner landed safely and the Cirrus aircraft landed under it CAPS parachute.
In episode #188 of my Aviation News Talk podcast, I talk with Cirrus Pilot Erik Gundersen, who put together a video that matches the aircraft ground tracks with the tower communications from the two controllers working the parallel runways at Centennial airport. After our conversation, I talk about some of the measurements and calculations I made after I talked with Erik, and how those factor into the accident. At the end, I give ten takeaways that all GA pilots can learn from this accident. You can find Aviation News Talk at: aviationnewstalk.com/blog for iPhone/iPad, or at aviationnewstalk.com/188 for Android and listening on a PC, or wherever you get podcasts.
It was clear from ADS-B data available through multiple sources, that the Cirrus was flying the traffic pattern at speeds at least 50 knots faster than the speeds specified by Cirrus. As Erik and I discussed, Cirrus states in their FOMs that the downwind should be flown at 100 knots, base at 90 knots, and final at 80 knots, and at slightly slower speeds for short field landings. Arguably, this accident would never have happened if the only change the pilot made was that he flew the correct pattern speeds.
Faster speeds require steeper bank angles to maintain the same turn radius. As Erik and I discussed, the faster you go, the larger the turn radius, which means at faster airspeeds, your turns become wider, unless you fly a steeper bank angle. Even at the very high speeds this aircraft was flying, if he had only increased his bank to 30 degrees, he would have actually turned just inside of 17R, the runway he was assigned. But since he was at a shallow bank angle, which I calculated to be about 18 degrees, he grossly overshot the centerlines of both runways.
A few people have suggested the Cirrus pilot was mistakenly headed for 17L. That’s certainly possible, as on numerous occasions, when flying to airports with parallel runways, I’ve had to intervene when a client started heading to the wrong runway. That seems to happen most often when the intended runway is shorter and less prominent than the larger runway to which they are mistakenly heading.
In this case though, it seems unlikely the Cirrus pilot was mistakenly headed for 17L, as he was also vastly overshooting that runway as well. I measured the angle at which the Cirrus pilot intersected the centerline for 17L, and it appears the Cirrus pilot still needed to turn another 56 degrees to be aligned with final. So he was less than halfway through the turn from base to final when he hit the Metroliner. So if he was mistakenly headed for 17L, he was doing a very poor job at lining up with that runway, as he was blowing through that centerline as well.
Here's a summary of my ten takeaways:
1. Fly the correct traffic pattern speeds
2. Faster speeds require steeper bank angles
3. Autopilots don’t bank steeply enough for use in the pattern
4. Get comfortable with 30 degree banks in the pattern
5. Don’t overshoot the final, but if you do, consider going around.
6. Refer to a traffic system to identify pattern traffic
7. If in doubt, start your turn early
8. Use G1000 and Perspective Track Vectors to eliminate overshoot final*
9. Don’t Get Distracted
10. Bring a parachute
*If you fly a G1000 or Perspective glass cockpit and are unfamiliar with these features, please buy my G1000 and Perspective book.
There are so many lessons to be learned from this accident, so please listen to this episode of my podcast. If you're unfamiliar with how to listen to podcasts, the easiest way to do it is to download one of our dedicated apps for your phone. Just go to the Apple App Store or the Google Play Store, and search for "Aviation News Talk." Or, click here for the dedicated app for iOS and dedicated app for Android. And podcasts are free, so they'll never cost you anything!
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