Coffin corner, a term commonly used in American football, refers to a specific section of the playing field where a punt or kickoff is received and the receiving team, unable to advance further, is forced to down the ball close to their own goal line. The spelling of coffin corner is pronounced /ˈkɔfɪn ˈkɔrnər/, using the International Phonetic Alphabet. The word coffin is pronounced with a "soft o" as in "coffee," and the stress is on the first syllable. Meanwhile, corner is pronounced with a "long o" and the stress on the second syllable.
Coffin corner is a term primarily used in aviation to describe a dangerous flight condition that occurs at high altitudes and high speeds, where an aircraft's stall speed approaches its critical Mach number. It refers to the narrow range between the maximum speed at which the aircraft can maintain level flight without stalling (known as the aircraft's critical Mach number) and its stall speed. This term originates from the analogy that an airplane operating in this critical phase is in a constraining situation similar to being trapped in a narrow coffin.
In this flight regime, the airflow over the wings becomes highly susceptible to shockwave formation due to the build-up of airflow pressure, resulting in a sudden loss of lift. This critical condition significantly limits an aircraft's manoeuvrability and control, making it extremely hazardous for pilots, often leading to loss of control and crashes.
To ensure safety during high-speed, high-altitude flights, pilots must be aware of their aircraft's operational parameters, such as critical Mach number, stall speed, and aerodynamic limits. They must carefully manage their speed and altitude to avoid entering the coffin corner, where the margin of error becomes very narrow.
Outside of aviation, the term "coffin corner" can also be used metaphorically to describe situations where an individual or organization is caught between two dangerous or difficult choices, resulting in a no-win scenario. This idiom can represent a predicament where various options may lead to unfavorable outcomes or consequences.
The term "coffin corner" has its origins in aviation and dates back to the early days of high-altitude flying. It refers to a dangerous flight condition that occurs when an aircraft is operating at the limits of its performance capabilities, specifically at a very high altitude and near its stall speed or critical angle of attack.
The etymology of the term is believed to come from a combination of two factors. Firstly, the word "coffin" refers to a box or a case in which a dead body is buried. It signifies the high-risk nature and potential fatal consequences of the flight condition. Secondly, the term "corner" alludes to the narrow region on an aircraft's performance chart representing the combination of altitude and airspeed that if exceeded, could lead to a loss of control or a stall, often resulting in a catastrophic outcome.