NBC Nightly News with Tom Brokaw


ACCIDENTS AND LESSONS LEARNED Within the last ten years, several accidents and near-accidents involving commuter planes, passenger jets and military aircraft have played a key role in shaping today's aviation safety and security standards. Whether the plane crash accentuated a flaw not yet found in the system or brought to light the imperfections of technology, it helped to broaden the way in which agencies including the National Transportation Safety Board and the Federal Aviation Administration approach safety and security issues. The following table provides descriptions of these accidents and the impact they had on the airline industry, the agencies that oversee them and on public safety.



Windshear Causes Fatal Crash On Aug. 2, 1985, a Delta Lockheed L-1011 jumbo jet en route to Ft. Lauderdale crashed near the Dallas-Ft. Worth Airport, killing 137. The jumbo jet struck two cars on a highway, killing one driver, before crashing into a field. Downdrafts of up to 80 mph from a storm passed north of the airport at about the time the Delta plane was making its approach. Control tower records also showed that the Delta pilot was told not to land, but did not respond to that warning. Notably, there were no procedures in place at the time for pilots facing low-altitude wind shear.				Improved Weather Radar System Today's pilots are required to undergo training to handle wind shear conditions and since 1993 their aircraft have been equipped with a system to detect wind shear conditions. Flying the final seconds of the Delta Flight 191 in a flight simulator is part of wind shear training. In 1995, the FAA sai d that an improved radar system to detect wind shear, called Terminal Doppler Weather Radar would be installed at 47 airports nationwide by 1997 or 1998.



Aging Plane Loses Fuselage in Flight On April 28, 1988, an Aloha Airlines flight going from Hilo to Honolulu suddenly lost an 18 foot section of its upper fuselage while cruising at 24,000 feet. The 19 year-old Boeing 737 landed safely, though 36 of its passengers were injured from flailing wires, metal strips and wind burn and one flight attendant was killed after being swept out of the aircraft's gaping hole. Metal fatigue and corrosion of the aging plane were blamed for the accident. Photo: Passengers still strapped into their seats are seen after Aloha Airlines Flight 243 lands safely.				Aging Aircraft Program The accident dramatically illustrated the issue of aging airliners and jump-started action on this issue by the FAA's Aging Aircraft Program. Although the FAA does not say at what age an aircraft should not be flown, it does have stringent maintenance requirements for older aircraft under the program.



Poor Cockpit Discipline Causes Crash Delta Flight 1141 crashed on Aug. 31, 1988 after take-off from Dallas-Ft. Worth International Airport, killing 12 passengers and two crew members. Following the crash of the Boeing 727, the National Transportation Safety Board examined Delta's take-off procedures, noting "poor cockpit discipline" by the flight crew as a probable cause of the crash. A tape of the cockpit voice recorder revealed that the flight crew joked about airline crashes just prior to take-off. The crew attempted to take off without the Boeing 727's wing flaps and slats properly extended. In addition, the plane's take-off warning system failed. Photo: Wreckage of Delta Flight 1141 is seen on a runway at Dallas Ft. Worth International Airport.				Improved Take-off Procedures After an FAA follow-up survey of Delta's flight operations and training manuals, the agency required a major revision of Delta Airlines' aircraft crew take-off checklists for all Delta aircraft. All aircraft flight crew are now required to double-verify all take-off procedures, once while holding on the taxiway, and a second time just before take-off. In addition, more than one crew member is required to verify each item on a checklist.



Bomb Brings Plane Down Over Scotland When Pan Am Flight 103 exploded over the town of Lockerbie, Scotland, all 259 people on board the Boeing 747, and 11 others on the ground, were killed. The plane was on its way to New York from Frankfurt via London. Investigators pointed the finger at a plastic explosive device planted by Libyan terrorists in a radio cassette player kept in the forward cargo hold of the plane. The device was loaded, undetected, onto the plane along with other baggage, at Frankfurt and transferred to the flight leaving from London's Heathrow International Airport. Photo: The wreckage of Pan Am Flight 103 in Lockerbie.				Stricter Airport Security Pan Am Flight 103 exposed the vulnerability of international flights to fatal acts of terrorism internationally and in the U.S. The White House called for more intensive checks on baggage being loaded onto airplanes and a more stringent security check of persons boarding all domestic and international flights. Many of these recommedations were incorporated into the 1990 Aviation Security Improvement Act.



Plane's Steering Controls Fail On July 19, 1989, a United Airlines DC-10 en route from Denver to Chicago flipped uncontrollably and crashed in a corn field near Sioux City, Iowa. Though 184 people survived, 112 of the 296 people aboard Flight 232 died in the crash. NTSB investigators later found that the plane's tail-mounted engine fan failed and disintegrated during flight, and caused the DC-10 to lose all hydraulic control. Photo: A rescue worker carries a child from the wreckage of flight 232.				New Hydraulics Systems Installed After the accident, aircraft were retrofitted with equipment to prevent the hydraulics from quitting all at once. This accident also changed the way all aging aircraft are maintained, especially in replacing parts sooner.



Two Planes Sent to the Same Runway At twilight on Feb. 1, 1991, 12 people in a Skywest Fairchild Metroliner commuter plane were waiting to take-off at a runway intersection when a US Air Boeing 727 landed on the same runway. All 12 people on the commuter plane and 22 people on the 727 were killed. One air traffic controller sent the commuter plane to the runway to await take-off, and later told the Boeing 727 to land on the same runway. Photo: Rescue crews put out the fire after the collision between a Boeing 727 and a commuter plane on a Los Angeles Airport runway.				Revised On-ground Traffic Rules In response to the Los Angeles collision, the FAA issued a rule limiting takeoffs from the middle of long runways. Specifically, the rule prohibits planes from entering runways at taxiway intersections and holding there for further clearance. The rule is in effect from sundown to sunrise, and around the clock at intersections that are not visible from control tower windows.



Plane Crashes on a Clear Night On a clear night on Sept. 8, 1994, a USAir Boeing 737 fell from the sky nose first and slammed into a wooded area near a small shopping center in Hopewell Township, Pa. The aircraft shattered on impact and all 137 people aboard Flight 427 were killed. Investigators initially speculated that the plane lost control after flying into the rotor wind, or high-energy, tornado-like spirals that are left in the tracks of an airplane in flight. Later, they refocused their attention on the rudder of the plane, citing other instances in which the flight controls in the Boeing 737 unexpectedly jam in flight.				Review of Rudder Problems Both this and a 1991 Colorado Springs plane crash give the NTSB and Boeing the opportunity to focus on the 737's rudder control system. NTSB investigators discovered that the Boeing 737's rudders can jam on rare occasions, and when pilots try to correct the problem, it could steer the plane in the opposite direction. In August 1996, the FAA prepared to make recommendations for changes in the flight control systems of the Boeing 737. In 1997, the FAA indicated that it will issue four Airworthiness Directives requiring all 737 operators to implement improvements, proposed by Boeing, to the rudder system within a two-year period. Photo: The rudder of a US Air Boeing 737.



Ice Brings Down Commuter Plane On its approach to Chicago O'Hare International Airport and after it ran into a dense, freezing drizzle, a propeller-driven American Eagle ATR-72 crashed after remaining in a holding pattern for more than one hour. Sixty-eight people on board Flight 4184 were killed. Later, the National Transportation Safety Board blamed the aircraft's manufacturer for failing to warn airlines and pilots about the vulnerability of that model aircraft's wings to ice accumulation. Photo: An American Eagle ATR in flight.				New De-icing Procedures for Small Planes The Federal Aviation Administration required ATR aircraft to install expanded de-icing equipment. The FAA also issued 18 "airworthiness directives" instructing pilots on how to recognize and escape from potentially hazardous icing conditions. The new rules applied to 29 relatively low-technology aircraft models. Photo: A newly improved ATR, before testing at Edwards Air Force Base, with a de-icing device that covers twice as much of the wing.



Pilot Error Leads to Crash On Dec. 13, 1994, the pilot of American Eagle Flight 3379, traveling from Greensboro to Raleigh-Durham, N.C., received a signal from the plane's control panels that one of the aircraft's engines had failed. While trying to determine which engine was the culprit, the pilots lost control of the aircraft and crashed, killing 15 of the 20 people on board. Investigators concluded that the pilot of the aircraft failed to follow the proper emergency procedures already established by the airline. The NTSB questioned American Eagle's training procedures. It later came out that American Eagle had hired the pilot without knowing that his previous employer, Comair, had suggested he resign due to poor performance.				Tracking Pilot Performance Commuter airlines did not have access to their pilots' previous employee records because there was no federal statute mandating that these records follow pilots from employer to employer. NTSB staffers proposed that the board ask the FAA to keep records of all pilots' evaluations and training sessions, and force airlines to share employee records with other airlines. Although the NTSB cited the pilot and questioned American Eagle's pilot training methods, it did not carry the proposal forward.



Oxygen Canisters Cause Explosion On May 11, 1996, a ValuJet DC-9 aircraft crashed into the Everglades shortly after contacting air traffic controllers at Miami International Airport and requesting an emergency landing. All 110 people on board Flight 592 were killed. A tape of the flight's cockpit voice recording showed that a fire had broken out on the aircraft. Issues such as the age of the aircraft and possible short-cuts in maintenance taken by the discount airline came into question. Later, NTSB investigators determined that volatile oxygen-generating canisters stowed in the jet's forward cargo hold activated and erupted into an inferno, causing the crash. Photo: NTSB investigators pointed to oxygen canisters like these as the cause of the fire that brought down a ValuJet DC-9.				Upgrade of Fire Detection Systems Major U.S. aircraft carriers voluntarily spent $400 million to install fire detectors in the aircraft cargo hold. Although there is a rule in place that mandates that no explosive materials be carried in the cargo hold of passenger planes, human error is at the center of this accident. Because the explosive materials, in this case the oxygen cannisters, were mislabeled as empty, they were loaded onto the aircraft.



Jumbo Jet Crashes Off New York Coast A TWA Boeing 747, originating in Athens and en route to Paris, had a three-hour layover at New York's Kennedy Airport on July 17, 1996. Shortly after take-off, Flight 800 plunged into waters off the coast of Long Island, New York, killing all 230 people aboard. Given the timing of this accident -- with the Summer Olympics in Atlanta -- initial speculation pointed to a terrorist bomb. Another theory arose when eyewitnesses claimed to have seen a fiery streak in the air just before the plane went down. After examining wreckage from the 747, investigators ruled out the bomb theory and instead focused on the aircraft's center fuel tank. A possible explosion in the tank could have brought the plane down. Photo: A piece of wreckage from TWA Flight 800 floats in the waters off Long Island, New York.				Fuel Tanks Under Review The NTSB continues to investigate possible causes for this crash. But recent speculation focuses on the aircraft's center fuel tanks and the possibility that an explosion occurred there and caused the plane to drop out of the sky. Photo: A graphic shows the location of the center fuel tank on the Boeing 747.



Military Causes Near Miss On Feb. 5, 1997, off the New Jersey coastline, a Navy air traffic controller gave two Air National Guard F-16s permission to begin their training exercises before a Nations Air 727 had cleared their airspace. The approach of the F-16s triggered the 727's T-CAS (Traffic Alert and Collision Avoidance System), which advised the passenger plane's crew to dive, climb and dive again to avoid a collision. After doing so, two flight attendants and a passenger were thrown to the cabin floor and were slightly injured. Though the T-CAS alarms were meant to increase safety and prevent collisions in mid-air, in this case, they created grave risk. Photo: An F-16 taxis out onto a runway.				Investigation Into Near-misses Following this incident, the Air Force issued a warning to all of its pilots to stay away from passenger aircraft, at a distance of at least 5,000 feet horizontally and 1,000 feet vertically. This near-miss also resulted in the opening of an NTSB investigation into other potential near-misses.