U.S. Department
of Transportation

Federal Aviation
Administration

St. Louis
Flight Standards District Office

10801 Pear Tree Lane
Suite 200
St. Ann, Missouri 63074

DECEMBER 1998

 

 

AVIATION SAFETY NEWSLETTER

www.faa.gov/fsdo/stlfsdo

Thought for the month.....The difference between taxes and the weather is that sometimes we can avoid the latter.

PROPER "SEASONING"....Despite the rather warm beginning, it is a certainty that this winter will produce nasty, cold weather. In addition to dropping temperatures, we can count on experiencing wind, snow, and ice - conditions which usually bring increased risks in aviation. It's human nature to avoid unpleasant conditions like this season can produce, but aviation is an outdoor activity. Preflight inspection and maintenance conducted outdoors is going to take longer and require additional dedication to be completed properly. If we're not in the fortunate group who can move to a more moderate climate for several months, we're stuck with it.

One of the most insidious enemies we can meet this winter is fog. There are all sorts of ways of classifying fogs, but they really all boil down to two main types - advection, caused by the horizontal movement of the air; and radiation, caused by loss of heat into space. In the Mid-West in winter, we get a lot of advection fog caused by warmer air moving over a colder surface. As opposed to radiation fog, which usually burns off by 10 AM, if a relatively warm air mass moves in after we've had snow, we can have advection fog which can remain in the area for several days.

Common "ground fog" is radiation fog, which is caused during the course of the night's cooling. This can play havoc with arrivals after dark, or early morning takeoffs. Advection fog is normally relatively dense and wide spread. Ground fog is usually relatively thin and found in patches. It begins in cooler, low lying areas and one of its more unpleasant characteristics is that an airport may be clearly visible when seen from overhead, causing a misconception that there isn't much to it. It may be only 100 feet thick, but the horizontal visibility can be close to zero. This has caused a nasty surprise for many an intrepid aviator, who suddenly finds the airport, and everything else, disappearing on short final, close to the ground.

Larger airports have sophisticated snow removal equipment, smaller airports do not, which means the quality of the surface we land on can vary greatly from place to place. If the storm starts with ice and freezing rain, then dumps a load of snow, we'll find many runways that are plowed clear of snow, but are still ice covered. The situation can get really dicey if the sun comes out for awhile and heats things up just enough to melt the ice, only to have things refreeze in the late afternoon as the temperature drops. Plowing may clear the landing surface but it often obscures lights, signs and surface markings. If an after dark arrival is anticipated, it might be a real good idea to call ahead to verify that the runway lights are going to be visible.

Unless the snow is loaded up and moved out, it must be pushed somewhere. Plowing leads to snow banks. An icy runway lined with three foot snow banks, is a guaranteed recipe for disaster unless the utmost care is exercised. Each progressive snow storm causes the runways and taxiways to become narrower. The first plowing was 50 feet wide. The second could only get to 45 and it raised the existing snow bank a foot and a half. More than one low wing operator has been surprised to have a wheel lifted off the ground as he inadvertently slid a wing up onto a snow bank.

True or false. When an aircraft begins to skid, you should turn the yolk in the direction of the skid. Answer - true. That way when the wing slams into the snow bank the aileron will be up, causing less damage. The real answer of course is not to allow the skid to begin. Turbo jet aircraft aren't as controllable on ice as propeller aircraft, but that's why you guys pay big bucks to live at airports that can afford to keep runways and taxiways clean. That's really important because jet engines love to eat loose ice. Because ice often has aerodynamic qualities, it can defeat many FOD protection systems and "fly" right into to turbine blades.

Aircraft that are brought out of a warm hangar can develop problems as they cool down. Any water that might be present will freeze, and flight controls that worked fine when they were checked inside, might not work as well after the aircraft has been in the cold for awhile. Helicopters on skids are great candidates for becoming frozen to the ground. Pilots must ensure that both skids are free before trying to lift up to a hover or dynamic rollover could occur.

Last, but not least, is a reminder to dress for survival. Sure, a light jacket is all we'll need once we get things running and warmed-up, but we need to consider the unlikely event that we might not land at our planned destination. An aircraft making an early morning departure before the tower opens, could easily go down just beyond the airport, and not be seen for several hours. Surviving a crash and then succumbing to hypothermia would be a double tragedy.

The recipe for winter operations simply requires the proper seasoning.

Upcoming Events:

Jan. 23
Boeing Building 33
Super Safety Seminar 8 AM to 1 PM.

Feb. 12 & 13
IA Renewal Seminar
Parks College at St. Louis University
Programs and exhibits

Feb. 13
Maintenance Seminar and Exhibit for Pilots and Mechanics
Programs and exhibits of interest to pilots, owners and maintenance technicians.
Parks College at St. Louis University

Feb. 20 & 21
Greater St. Louis Flight Instructors Association Flight Instructor Renewal Clinic
Parks College at St. Louis University

HAVE A GREAT HOLIDAY SEASON

LET'S NOT MEET BY ACCIDENT
FRED P. HARMS

Safety Program Manager

1-800-322-8876 x 4835

Fred.Harms@faa.gov

"May Day"