January 1, 2008
By Bruce Landsberg
What better way to start the new year than with a remembrance that good decision making is part of every flight? This business related flight took place on February 22, 2006, in an aircraft that was ill suited for the job.
The plan was to fly from Warrenton, Virginia, to Mitchellville, Maryland, in a Cessna 172 and pick up a passenger before continuing to Atlantic City, New Jersey. Moderate icing had been predicted, along with snow, low ceilings, and marginal visibility. The ATP-rated pilot, a private pilot without an instrument rating, and a passenger departed Warrenton under IFR for Freeway Airport (W00) in Mitchellville, Maryland.
About 8 a.m. Eastern Standard Time (EST) a pilot telephoned to ask the Freeway airport manager about the weather. The ceiling at the time was 500 feet overcast with one-mile visibility in rain. These conditions were already below landing minimums for the approach into that airport. The pilot said he would be arriving about 8:30 a.m. A few minutes later a passenger showed up, expecting a flight from Warrenton, Virginia.
The trip proceeded routinely, and the Potomac Tracon cleared the flight for the RNAV (GPS) Runway 36 approach at Freeway Airport. Although the approach qualifies as a straight in, it is not aligned with the runway. This feature compounds the chore of finding the runway at the minimum descent altitude (MDA) because any wind correction angle must be applied to the approach course. In addition, this short (2,420 feet), narrow (40 feet) runway has obstructions at both ends.
Radar data showed the Cessna approaching from the south and tracking the final approach course inbound. About 9:30 a.m. the pilot announced on the CTAF that he was five miles from the airport and inbound on the RNAV 36 approach. The airplane overflew the airport at about 500 feet, and the pilot then asked whether the runway lights were illuminated. The airport manager responded that the lights were on but recommended that the flight continue to Baltimore-Washington International Airport (BWI), 14 miles north, for landing, because the “visibility was only one-half mile in heavy snow.” The pilot did not respond.
The Cessna executed a missed approach and was vectored for a second attempt. The controller asked what the weather conditions were during the first attempt, and the pilot responded, “[the clouds were] broken at 600 to 700 but we couldn’t see the runway.” During the second approach, the airplane descended and leveled at about 500 feet msl. The last radar hit was observed at 400 feet msl, about one-quarter mile prior to the approach end of Runway 36. Witnesses at the airport saw the 172 appear over the south end of the runway—between 200 and 300 feet above the ground—and fly the length of the runway at low altitude. At the north end of the runway, the airplane turned west away from the airport, then circled to the right in a “dramatic” and “nose-high attitude” back toward the runway. It flew down the runway southbound and turned west again. Engine power increased, and the flaps were retracted. At 9:50 a.m. the Cessna entered a steep left bank back toward the airport and “nose-dived” out of view. Both pilots were killed, and the rear-seat passenger received serious injuries.
The pilot held an airline transport pilot certificate and a flight instructor certificate with airplane single engine, multiengine, and instrument ratings. He reported 2,900 total hours of flight time on his last medical. No age was reported.
The second pilot held a private pilot certificate, with no instrument rating, and had about 180 total hours logged.
The 2001 Cessna 172 had approximately 2,411 total hours with a 100-hour inspection completed a few weeks before. It was equipped with an IFR-capable Bendix/King KLN 94 GPS receiver, and a Bendix/King KMD 540 multifunction display. The GPS navigation and multifunction database cards were expired. The NTSB could find no malfunction relative to engine, instruments, or flight controls.
At 9:41 a.m. EST, Andrews Air Force Base, nine miles southwest of Freeway Airport, reported scattered clouds at 300 feet and an overcast layer at 500 feet, with two miles of visibility in snow and fog. The wind was from 140 degrees at 3 knots. At 9:42 EST, the weather reported at BWI, 14 miles north of Freeway Airport, included broken clouds at 500 feet and an overcast layer at 900 feet with three-quarters of a mile of visibility in snow and fog. The wind was from 160 degrees at 3 knots. Witnesses at Freeway Airport said the clouds were “on top of the trees” and that visibility was about one-half mile because of snow and fog.
This accident makes an excellent case study about poor decision making. We’ll start with the big errors.
Error one: The weather alone should have caused the pilot to cancel the flight. A Cessna 172, or any light aircraft without deicing capability for that matter, is just not reliable or safe transportation in a winter storm. If your travel profile requires regular winter trips outside of the sunny south, approved deicing equipment is needed. The airport manager’s early morning report of rain indicates that the weather was relatively warm and wet on the front side of the low-pressure system or front. Be patient. It will likely generate moderate to severe ice at some point, and flights in non-deiced aircraft in February in the Mid-Atlantic region are best restricted to gentle IFR and VFR. The fact that the flight didn’t get ice is only a result of luck and timing.
Error two: The choice of airport was poor. The MDA for the RNAV (GPS) Runway 36 approach at Freeway was 532 feet agl with a minimum visibility of one mile. Even before takeoff, the pilot knew the weather was right at minimums. Weather does fluctuate, however, and under FAR Part 91, we’re allowed to take a look even if weather is reported below minimums. Though we should cherish that freedom, most of us are better served to plan for a different airport. This NTSB report does not state whether the pilot filed an alternate, which certainly would have been required under the prevailing weather conditions, but logic and safety also dictate that it would have been smart to have a plan B. The pros would have told the passenger to go to BWI, where there’s a full ILS, plenty of runway, snow removal, and a complete lighting system to make finding that runway much easier.
Error three: The aircraft did not have the useful load needed. The NTSB calculated that the Cessna weighed 2,604 pounds at takeoff—147 pounds above the maximum gross weight of 2,457 pounds. At the time of the accident, based on nominal fuel consumption, the airplane weighed about 2,526 pounds—69 pounds above gross. They were about to pick up a second passenger at Freeway who weighed 175 pounds. Now, think this through. The airplane would have been nearly 240 pounds overweight, taking off from a short runway with obstacles. The runway was contaminated with snow that would have extended the takeoff roll. Even if the flight had successfully landed, I have doubts about how successful the next takeoff would have been.
Error four: If the first approach is on speed and on altitude (it should be if you’re flying in weather) and the runway isn’t there, strongly consider diverting to the alternate. The accident files show that a disproportionate number of accidents occur on subsequent approaches as the pilot tries a little harder to get in. That’s a judgment call, but I can cite dozens of accidents following multiple approaches.
Error five: Every pilot should know that stall speed increases with weight, bank angle, and abrupt control input. It’s a virtual certainty that Cessna never tested the 172 under these weight conditions. The stall-speed chart in the 172R Skyhawk information manual shows that at maximum gross weight, at the most rearward center of gravity, and with a 10-degree flap setting, the airplane would stall at 58 knots in a 45-degree bank and at 69 knots at a 60-degree bank. But the flaps had been retracted, which raised the stall speed. Overweight and off the stall speed chart at a mere 300 feet above the ground is no-man’s land. A note at the bottom of the chart states: “Altitude loss during a stall recovery may be as much as 230 feet.” You’ll recall that the witnesses put the aircraft at between 200 and 300 feet agl.
The NTSB determined the probable cause to be, “The pilot’s improper in-flight planning/decision to attempt a landing in weather conditions below landing minimums, and his failure to maintain airspeed while maneuvering. Factors in the accident were the fog and snow.”
Why is this a landmark accident? Simply because the bad aeronautical decision making (ADM) discussed here infects a few pilots regularly. In this example, a moderately experienced ATP/CFI is sure he can handle it. He’s been flying long enough to have seen quite a bit, but the list of errors is extensive and any one might have been enough to precipitate an accident. Taken collectively, it’s impressive, and with enough bad decision making, one can overcome any skill level.
I’ll have more to say about ADM next month in my monthly column “Safety Pilot,” but much of it comes from trying to get too much utility out of an aircraft, and in this case it’s plausible that the VFR pilot was hoping to learn more about how to fly in instrument weather. The knowledge gained from that lesson was very short lived. The ATP wanted to provide service, and a business trip seemed like a perfect opportunity. The intentions weren’t bad, but the outcome certainly was.
Bruce Landsberg is executive director of the AOPA Air Safety Foundation.
To read NTSB reports about this and similar accidents, visit the ASF Web site.
To hear a real pilot story on how Cessna 172s fly in IMC with ice, visit the Web site and click the “Real Pilot Stories” link. On the resulting page, select “Iceman.” The AOPA Air Safety Foundation also offers publications on strategies for dealing with ice on its ”Safety Publications and Articles” page. Be sure to check out the new interactive course on aeronautical decision making in “Interactive Courses.”
Safety and Education,
Pilot Training and Certification,
VFR into IMC
The NTSB has organized a safety seminar May 10 to focus on aerodynamic stalls and loss of control, a leading cause of general aviation fatalities.
According to the most recent Joseph T. Nall Report, in 2010 there were 43 accidents involving weather, and 28 of them were fatal. In fact, weather accidents are the most consistently fatal types of accidents.
The management team running Chelton Flight Systems and S-Tec Corp. in Mineral Wells, Texas, for parent Cobham Avionics saw an opportunity and bought in.
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