SAFETY ENVELOPE.A Curtiss-Wright P-40N, like this one, was lost in an aerobatics accident off the Atlantic Ocean shore of New York. Additional altitude likely would have saved the pilot.
Ensuring that there’s a safety margin in everything we do is fundamental to aviation accident avoidance. It’s when we tinker at the extreme edges of the safety envelope that we set the stage for getting hurt. Extremes can be reached by factors we bring to the table, or they could be imposed upon us and require our recognition and action.
In one accident investigated by the NTSB, the pilot was doing something with which he was familiar, but for which additional altitude would have enhanced his margin of safety. His Curtiss Wright P-40N, which was built in 1944, crashed into the Atlantic Ocean just off Mastic Beach, N.Y., while the pilot was practicing aerobatics. The pilot’s son told investigators that he and his father performed in air shows. During this practice session, the son was on the beach acting as a safety guide and communicating with his father using a handheld radio. The commercial pilot was killed. Visual meteorological conditions existed. The airplane had taken off from the Brookhaven Airport, Shirley, N.Y.
The pilot’s son reported that his father had put the airplane into a “half Cuban eight” maneuver at an estimated 250 to 260 mph. The airplane slowed down during the maneuver, to about 100 to 120 mph. In the middle of the Cuban eight, it went into a spin. The airplane was too low to permit recovery from the spin before impact with the water.
Investigation revealed that the pilot had been issued an FAA Certificate of Waiver or Authorization to perform aerobatics in a box of airspace off the coast. However, the FAA found that the pilot failed to file a NOTAM that the airspace would be in use and didn’t notify ATC to activate the box prior to beginning aerobatic activity as required. The NTSB determined that the probable cause of this accident was the pilot’s failure to maintain adequate airspeed while performing aerobatics at low altitude.
Unless you’re a pilot for the National Oceanic and Atmospheric Administration’s (NOAA) Aircraft Operations Center, you’re not likely to deliberately do extreme flying into extreme weather. NOAA operates a Gulfstream G4, a Citation II, two de Havilland Twin Otters, a couple of Aero Commanders and other assorted airplanes and helicopters for projects like gathering data on hurricanes. NTSB accident files demonstrate that pilots continue to inadvertently find themselves trying to get out of extreme flying conditions precipitated by weather.
A Piper PA-60-602P Aerostar suffered an in-flight breakup in the vicinity of Camp Hill, Ala., while on a Part 91 business flight. At the time, the pilot was trying to reverse course to avoid what appeared on radar to be an intense to extreme radar echo depicting a level-5 to level-6 thunderstorm. The airplane was on an IFR flight plan, in instrument conditions. The private pilot and his passenger were killed. The flight departed Habersham County Airport, Cornelia, Ga.
The pilot had telephoned flight service to be briefed for an IFR flight to Mobile, Ala. The briefer warned of a line of embedded thunderstorms along the route from Atlanta to Mobile including SIGMETs and advised that tops were forecast to be at 41,000 to 50,000 feet. The specialist suggested that the pilot might land at an intermediate stop ahead of the weather, possibly in Pensacola, Fla., or farther north in Crestview, Fla., wait for the storms to pass and then continue the flight to Mobile. The pilot filed an IFR flight plan from Cornelia, Ga., to Pensacola at 16,000 feet. The pilot then called back to obtain his clearance. The flight service specialist put the pilot on hold while he worked out a void time with ATC. When the specialist picked up again, the pilot was no longer on the line.
The pilot departed Cornelia without an IFR clearance and contacted Atlanta ARTCC. The controller advised the pilot that he wasn’t on his assigned heading, altitude or correct transponder code, and subsequently handed the pilot off to another controller. The flight was subsequently cleared direct to Panama City, Fla., and the pilot was instructed to climb to 16,000 feet. The pilot then radioed that “...we’re going to make a reverse.” The controller responded, “Roger,” and there were no further communications.
Radar data showed that the airplane was level at 16,000 feet heading southwest, and then began a continuous left turn northwest-bound and descended to 15,700 feet, then 15,600 feet, then dropped off radar.
Atlanta ARTCC had broadcast weather alerts for the route the accident airplane was following over the radio frequency the pilot was on. There was a line of thunderstorms 40 nm wide, and moving from 280 degrees at 35 knots. The tops of the thunderstorms were at 44,000 feet, with two-inch hail and possible wind gusts up to 60 knots.
A weather study conducted by the NTSB revealed the pilot penetrated an intense to extreme VIP level-5 to level-6 weather radar echo. The thunderstorm contained strong horizontal and vertical winds, heavy rain, turbulence, icing and instrument flight conditions. The cloud tops of the cell the Aerostar penetrated were near 38,000 feet and the freezing level was near 14,000 feet.
The NTSB found that the controllers failed to comply with FAA directives regarding the issuance of severe weather information by not advising the pilot of the weather displayed on the radar controller’s scope. According to the recorded display system information, the controllers should have been able to see that there was moderate to extreme weather depicted along the airplane’s flight track.
The airplane’s Pilot’s Operating Handbook says that, in turbulent air, the pilot should reduce airspeed to 166 knots indicated or less and fly attitude (autopilot altitude hold off) and avoid abrupt maneuvers. It continues, “In conditions of extreme turbulence, reduce airspeed to maneuvering speed or slightly less. Maneuvering speed decreases with the weight of the airplane—e.g., 166 KIAS at 6,000 pounds and 152 KIAS at 5,000 pounds. A reduction in airspeed will lower the stress to which the airplane is subjected by turbulence. Fly attitude and avoid abrupt maneuvers. Fasten seat belts and shoulder harness securely as a precaution against buffeting and lurching. When flying in extreme turbulence or strong vertical currents and using an autopilot, the altitude-hold mode should not be used.”
The NTSB determined that the probable cause of this accident was the pilot’s continued flight into known thunderstorms resulting in an in-flight breakup. A factor in the accident was the air traffic controller’s failure to issue to the pilot the extreme-weather radar echo intensity information that was displayed on his screen.
The flight crew of Pinnacle Airlines flight 3701 decided to deliberately try some extreme flying by doing something there was no compelling reason to do: going to the airplane’s service ceiling. As a result, the Bombardier CL-600-2B19 crashed into a residential area about 2.5 miles south of Jefferson City Memorial Airport (JEF), Jefferson City, Mo., in October 2004. The airplane was on a repositioning flight from Little Rock, Ark., to Minneapolis, Minn. During the flight, both engines flamed out after a pilot-induced aerodynamic stall and were unable to be restarted. The captain and the first officer were killed, and the airplane was destroyed.
The captain had asked ATC for a climb to 41,000 feet, the airplane’s maximum operating altitude. The cockpit voice recorder revealed the captain and the first officer discussed the climb to 41,000 feet, with the first officer stating, “Man, we can do it. Forty-one it.” After the airplane reached its maximum altitude, the CVR recorded the first officer laughing as he stated, “This is great.” The controller radioed, “I’ve never seen you guys up at 41 there.” The captain replied, “We don’t have any passengers on board so we decided to have a little fun and come on up here.” The captain added, “This is actually our service ceiling.”
After a while, the captain told the first officer, “We’re losing here. We’re gonna be coming down in a second here.” About three seconds later, the captain stated, “This thing ain’t gonna hold altitude, is it?” The first officer responded, “It can’t, man. We (cruised/greased) up here but it won’t stay.” The captain stated, “Yeah, that’s funny we got up here; it won’t stay up here.” The captain radioed the controller, “It looks like we’re not even going to be able to stay up here, look, for maybe three nine oh or three seven (lower altitudes, 39,000 or 37,000 feet).” The flight data recorder showed activation of the stall warning stick shaker. The airspeed had decreased to 150 knots, and angle of attack was about 7.5 degrees. The angle of attack continued increasing, eventually reaching 29 degrees. The engines flamed out. The airplane began a roll, reaching 82 degrees left wing down. The crew declared an emergency and, unsuccessfully, tried to restart the engines as the airplane descended.
The NTSB determined that the probable cause of this accident involved the pilots’ unprofessional behavior, deviation from standard operating procedures and poor airmanship. Additional issues included pilot training and the published procedures for engine restarts.