USAir Flight 427
| USAir Flight 427 | |
|---|---|
.jpg) A Boeing 737-300 of USAir |
|
| Accident summary | |
| Accident type | Loss of control |
| place | Hopewell Township, Beaver County, Pennsylvania |
| date | September 8, 1994 |
| Fatalities | 132 |
| Survivors | 0 |
| Injured | 0 |
| Aircraft | |
| Aircraft type | Boeing 737-3B7 |
| operator | USAir |
| Mark | N513AU |
| Departure airport | Chicago O'Hare International Airport |
| Stopover | Pittsburgh International Airport |
| Destination airport | Palm Beach International Airport |
| Passengers | 127 |
| crew | 5 |
| Lists of aviation accidents | |
On September 8, 1994, a Boeing 737-3B7 crashed on USAir flight 427 when approaching Pittsburgh due to a sudden full deflection of the rudder . All 132 occupants were killed in the accident.
the accident
The USAir's Boeing 737 was on a scheduled flight from Chicago to Palm Beach with a scheduled stopover in Pittsburgh. The pilot in charge was Peter Germano, 45, with 12,000 flight hours, his first officer was Charles B. Emmett, 38, with 9119 flight hours.
For the approach to runway 28R in Pittsburgh, Flight 427 was queued behind a Boeing 727-200 of Delta Air Lines . According to the radar record, the two planes never got closer than 4.1 miles. At 7:02:57 p.m., there were three dull thumps followed by a click and a louder thump. At the same time, the pilots lost control of the aircraft at an altitude of around 600 meters (1800 feet). The aircraft tilted over the left wing and went into a dive. The Boeing 737 hit a wooded area at an angle of 80 degrees to the transverse axis and rotated 60 degrees to the left around the longitudinal axis and exploded. The 127 passengers and five crew members died in the impact.
Cause of accident
After more than four and a half years of investigation, the National Transportation Safety Board (NTSB) concluded that the pilots had lost control of the aircraft due to a sudden full deflection of the rudder . The rudder deflection was caused by a blocked servo valve in the Main Rudder Power Control Unit (PCU) , i.e. the current regulation of the main rudder, which also controls the yaw damper . Due to the malfunction, the neutral position of the rudder was shifted so that it suddenly deflected to the left and responded in the opposite direction to the controls. Due to the low altitude, it was not possible for the pilots to intercept the aircraft. The PCU of the affected Boeing 737 series was then modified by the manufacturer.
Previously, an identical problem caused the crash of United Airlines Flight 585 on March 3, 1991, according to NTSB ; Similar rudder malfunctions, partly for different reasons, occurred among others on a Boeing 737-200 of Continental Airlines (1994), Eastwind Airlines (1996, due to an electrical short circuit) and MetroJet (1999). Another suspected case was the Silk Air flight 185 carried out by a Boeing 737-300 on December 19, 1997 , the cause of the crash could not be clearly clarified.
Varia
- After the disaster, USAir struggled to compile a passenger list as some Energy Department employees were booked for a later flight but took flight US427 instead.
- Flight number US427 was then no longer used.
- For the USAir, this was the second fatal accident in two months; USAir flight 1016 previously crashed on the approach to Charlotte Airport .
- Among the victims was the well-known behavioral biologist and neuroethologist Walter Heiligenberg .
- Ten kilometers west of the crash site, also in Beaver County , is the Beaver Valley Nuclear Power Plant .
Individual evidence
- ↑ Official accident report of the NTSB (in English)
- ^ " 28 Seconds of Horror ( Memento March 10, 2005 on the Internet Archive )," Pittsburgh Tribune Review
- ^ Final report of the NTSB
- ^ St. Petersburg Times, 2006 , accessed December 1, 2017