physics

USAir Flight 427

USAir Flight 427 is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand USAir Flight 427 rather than just read about it. In short: USAir Flight 427 was a scheduled flight from Chicago's O'Hare International Airport to Palm Beach International Airport, Florida, with a stopover at Pittsburgh International Airport. On Thursday, September 8, 1994, the Boeing 737-300 flying this route crashed in Hopewell Township, Beaver County, Pennsylvania while approaching Runway 28R at Pittsburgh, which was USAir's largest hub at the time.

Key takeaways

USAir Flight 427 belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect USAir Flight 427 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of USAir Flight 427 from memory before moving on to harder problems.

Reference excerpt

USAir Flight 427 was a scheduled flight from Chicago's O'Hare International Airport to Palm Beach International Airport, Florida, with a stopover at Pittsburgh International Airport. On Thursday, September 8, 1994, the Boeing 737-300 flying this route crashed in Hopewell Township, Beaver County, Pennsylvania while approaching Runway 28R at Pittsburgh, which was USAir's largest hub at the time. This accident was the second longest air crash investigation in history. The investigation into USAir 427 helped to also solve the crash of United Airlines Flight 585. The National Transportation Safety Board (NTSB) determined that the probable cause was that the aircraft's rudder malfunctioned and went hard over in a direction opposite to that commanded by the pilots, causing the plane to enter an aerodynamic stall from which Captain Peter Germano and First Officer Charles B. Emmet III were unable to recover. All 132 people on board died, making the accident the deadliest air disaster in Pennsylvania's history. The reports indicated that hot hydraulic fluid entering the rudder's dual servo valve froze, causing the rudder to work in the opposite direction.

Background

Aircraft The aircraft involved, manufactured in 1987, was a Boeing 737-3B7 registered as N513AU with serial number 23699. It had logged a total of 23,846 hours of flight time and performed 14,489 take-off and landing cycles. It was powered by two CFM International CFM56-3B-2 engines.

Crew The flight crew consisted of Captain Peter Germano, aged 45, who was hired by USAir on February 4, 1981, and First Officer Charles B. "Chuck" Emmett III, aged 38, who was hired in February 1987 by Piedmont Airlines (which merged into USAir in 1989). Both were regarded as excellent pilots and were very experienced: Germano logged approximately 12,000 flight hours, including 4,064 on the Boeing 737, while Emmett logged 9,119 flight hours, 3,644 on the 737. Flight attendants Stanley Canty and April Slater were hired in 1989 by Piedmont Airlines. Flight attendant Sarah Slocum-Hamley was hired in October 1988 by USAir.

Accident

In its arrival phase approaching Pittsburgh, Flight 427 was sequenced behind Delta Air Lines Flight 1083, a Boeing 727-200. At no time was Flight 427 closer than 4.1 miles (6.6 km) to Delta 1083, according to radar data. Flight 427 was on approach at 6,000 feet (1,800 m) altitude, at flaps 1 (eight degrees) configuration, and at approximately 190 knots (220 mph; 350 km/h). At 19:02:57, the aircraft entered the wake turbulence of Delta 1083, and three sudden thumps, clicking sounds and a louder thump occurred, after which the 737 began to bank and roll to the left. The autopilot disconnected, and First Officer Emmett stomped on the right rudder pedal, and held it there for the remainder of the flight, unaware that the rudder had reversed hard to the left. As the aircraft's heading and bank angle skewed dramatically to the left, Emmett and Germano both rolled their yokes to the right and pulled back on the elevators to counter the gradually decreasing pitch angle, as the stick shaker activated and the airplane entered an aerodynamic stall, caused by the wing's critical high angle of attack. As the stick shaker activated, Germano exclaimed "Hold on!" frequently, while Emmett, under physical exertion, said, "Oh shit!" Germano exclaimed, "What the hell is this?" As Pittsburgh air traffic control noticed Flight 427 descending without permission, and requested for them to return to 6,000 feet (1,800 m), Germano keyed the microphone and stated, "Four-twenty-seven, emergency!" Under duress, Germano left the microphone keyed for the rest of the accident; the ensuing exclamations in the cockpit were heard in the tower at Pittsburgh. The aircraft completed one full roll, remaining in a nose-down pitch. Trying to counteract sharply rising G-forces, Germano yelled "Pull!" three consecutive times before screaming, during which Emmett stated "God, no" seconds before impact. Pitched 80° nose-down and banked 60° left while traveling at approximately 300 mph (260 kn; 480 km/h), the 737 slammed into a gravel road in a wooded ravine and exploded at 19:03:25 in Hopewell Township, Beaver County, near Aliquippa, approximately 28 seconds after entering the wake turbulence. At the time of the accident, many people had gathered at the nearby Hopewell Soccer Club Fields for evening soccer practice. These people witnessed the crash of the aircraft and described the plane as suddenly falling out of the sky. The aircraft narrowly missed impacting the I-376 interchange just east of the Green Garden shopping plaza, where some witnesses took cover. Power was knocked out in the Giant Eagle after the crash. After several failed attempts to raise the downed flight on radar, Pittsburgh air traffic control raised the alarm and local fire companies and EMS were hailed. Upon arriving at the scene, however, the aircraft was found to be obliterated, and not only was it evident that there were no survivors, but the fragmented human remains constituted a bio-hazard. All 132 aboard Flight 427 were killed, in the state of Pennsylvania's deadliest aviation accident to date.

Investigation

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with USAir Flight 427

Start with the simplest possible case. Write down what USAir Flight 427 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to USAir Flight 427 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about USAir Flight 427 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of USAir Flight 427

In research: USAir Flight 427 appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses USAir Flight 427 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: USAir Flight 427 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1994 in Pennsylvania, Airliner accidents and incidents caused by design or manufacturing errors, Airliner accidents and incidents caused by mechanical failure, so understanding it makes those chapters shorter.
In everyday life: Look for USAir Flight 427 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study USAir Flight 427 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what USAir Flight 427 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain USAir Flight 427 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is USAir Flight 427 in simple terms?

Why does USAir Flight 427 matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study USAir Flight 427?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on USAir Flight 427.