Page 18 - April 2016

16 • TWIN & TURBINE APRIL 2016From the Flight DeckOwl Snot, Slippery As...by Kevin R. Dingmanair transportation. It also caused the second event in 40 years when I couldn’t stop my airplane due to SaOS surfaces. On the last day of a four-day trip, we were reassigned to work from RDU to DFW then deadhead (ride in the cabin) to ORD. We would take off two hours earlier (at 0550) than originally scheduled and get to ORD four hours later. During the ride to the airport, it started to rain– kind of. As I like to say, the rain hitting the windshield sounded a little “thick.” By the time we exited the van at the RDU terminal, the ground was coated with a quarter-inch of ice and snow pellets. Our plane had been on the ramp overnight and was coated as well. The deicing location is on the opposite side of the field from our gates. Taxiway Charlie in that direction is uphill going east and of course, downhill coming back west. We were one of the first to taxi that morning so little was known of field conditions and none of the taxiways had yet been cleaned. Since we would be nearer 5R after deicing, ground suggested we use that runway. They were working on cleaning 5L (10,000) but 5R (7,500), was already clean. Cleaned by a unique machine with, apparently, a confusing name....as in, slipperier than. Before DuPont scientist Roy Plunket accidentally discovered Teflon in 1938, engineers at Fiction Friction, LLC were coaxing owls to excrete the substance, analyzing its molecular structure. What, you’ve never seen an owl sneeze into a beaker? The project was abandoned after a marketing test with homemakers was snot received well. Long before this, archeologists had discovered that O.S. was the secret in moving blocks to build the pyramids. It wasn’t aliens, it was owls.SaOS/MμMechanics and machinists reference the slippery compound when describing a lubricant that works really well; it’s perfect. Machine parts using a lubricant with a coefficient of friction (Mμ – pronounced: mew) comparable to the owl’s natural and biodegradable emollient would never, ever experience wear. Even though my suggestions to include a reference to the material in the AIM have been ignored, an excellent method to categorize extremely poor braking action is to use the SaOS / Mμ: Slippery-as-Owl Snot / coefficient of friction (© 2016). It’s one notch slipperier than nil-braking and could be used for any reports of less than 0 on the ICAO Mμ scale.What brings up such a disgusting description and fabricated history? And why the need to debate another reference for indescribable slipperiness? Well, my fellow aviators (which includes 216 species of owls, btw), to wit: for only the second time in 40 years of using aerodynamic and mechanical devices (wheel brakes, spoilers, speed brakes, thrust reversers, a tail hook, drag chute and once a cabin door) in order to stop my flying machine, I couldn’t stop. This time it was a140,000 pound airliner going down a sloped taxiway – with another airliner in front of me experiencing the same SaOS/Mμ. The first time was in a Cherokee 140 in Plainwell, Michigan (61D) in 1975.This Fool EscapedThe runway in Plainwell is East/ West and 2,650 feet long. Plenty of room for the mighty Cherokee piloted by a modest, but brilliant, teenager. Unless, that is, the runway is SaOS. The field is uncontrolled, no other aircraft were on CTAF, no one manned the FBO radio and it was night. No one was there to provide a field report. I was with a high school buddy and we landed to the East, close to the right spot but a bit long. A couple of seconds after touching down I applied the toe brakes. Nothing. Release and re-apply. Nothing. I quickly unlatched the cabin door and instructed my friend to hold it open against the wind. Using full-up stabilator and the open door, I was able to slow to about twenty knots before we ran out of runway. As the end of the runway neared, with a three foot berm of snow approaching the nose, I remember thinking that I didn’t want the prop to hit the snow bank. Out of intuition, instinct or fear, I shoved the right rudder pedal to the floor. We slid 90 degrees sideways the last 100 feet, coming to rest with the left wing three feet over the berm. Thank you, Piper, for wing dihedral. No problem: taxi to the FBO, drop off my friend, and head back to AZO. It was one of a handful of times that fate was the hunter and this fool escaped.Thick RainOne final blast of cold, wet weather rolled through the Eastern U.S. recently. Winter’s parting shot wreaked havoc on both surface andMμValue40 or greater 36 to 3926 to 2930 to 4020 to 2520 to 0Less than 0Braking Action GoodMed / Good Med / Fair FairPoor Nil SaOS