Henry John Deutschendorf Jr. (December 31, 1943 – October 12, 1997), known professionally as John Denver, was an American singer and songwriter. He was one of the most popular acoustic artists of the 1970s and one of the best-selling artists in that decade. AllMusic has called Denver "among the most beloved entertainers of his era".

Denver recorded and released approximately 300 songs, about 200 of which he wrote himself. He had 33 albums and singles that were certified Gold and Platinum in the U.S by the RIAA, with estimated sales of more than 33 million units. He recorded and performed primarily with an acoustic guitar and sang about his joy in nature, disdain for city life, enthusiasm for music, and relationship trials. Denver's music appeared on a variety of charts, including country music, the Billboard Hot 100, and adult contemporary, earning 12 gold and four platinum albums with his signature songs "Take Me Home, Country Roads", "Poems, Prayers & Promises", "Annie's Song", "Rocky Mountain High", "Calypso", "Thank God I'm a Country Boy", and "Sunshine on My Shoulders".

Denver appeared in several films and television specials during the 1970s and 1980s, including the 1977 hit Oh, God!, in which he starred alongside George Burns. He continued to record into the 1990s, also focusing on environmental issues as well as lending vocal support to space exploration and testifying in front of Congress to protest censorship in music. Known for his love of Colorado, Denver lived in Aspen for much of his life. In 1974, Denver was named poet laureate of the state. The Colorado state legislature also adopted "Rocky Mountain High" as one of its two state songs in 2007, and West Virginia did the same for "Take Me Home, Country Roads" in 2014.

Denver died on the afternoon of October 12, 1997, when his light homebuilt aircraft, a Rutan Long-EZ with registration number N555JD, crashed into Monterey Bay near Pacific Grove, California, while making a series of touch-and-go landings at the nearby Monterey Peninsula Airport. He was the plane's only occupant. The official cause of death was multiple blunt force trauma resulting from the crash.

Denver was a pilot with over 2,700 hours of experience. He had pilot ratings for single-engine land and sea, multi-engine land, glider and instrument. Denver also held a type rating in his Learjet. He had recently purchased the Long-EZ aircraft, made by someone else from a kit,[61] and had taken a half-hour checkout flight with the aircraft the day before his accident.

Denver was not legally permitted to fly at the time of the crash. In previous years, he had been arrested several times for drunk driving. In 1996, nearly a year before the accident, the FAA learned that Denver had failed to maintain sobriety by not refraining entirely from alcohol and revoked his medical certification. However, it was determined that the crash was not caused or influenced by alcohol use; an autopsy found no signs of alcohol or other drugs in Denver's body.

The post-accident investigation by the National Transportation Safety Board (NTSB) showed that the leading cause of the accident was Denver's inability to switch fuel tanks during flight. The quantity of fuel had been depleted during the plane's flight to Monterey and in several brief practice takeoffs and landings Denver performed at the airport immediately before the final flight. His newly purchased amateur-built Rutan aircraft had an unusual fuel tank selector valve handle configuration. The handle had originally been intended by the plane's designer to be between the pilot's legs. The builder instead put it behind the pilot's left shoulder. The fuel gauge was also placed behind the pilot's seat and was not visible to the person at the controls. An NTSB interview with the aircraft mechanic servicing Denver's plane revealed that he and Denver had discussed the inaccessibility of the cockpit fuel selector valve handle and its resistance to being turned.

Before the flight, Denver and the mechanic had attempted to extend the reach of the handle using a pair of Vise-Grip pliers, but this did not solve the problem, and the pilot still could not reach the handle while strapped into his seat. NTSB officials' post-accident investigation showed that because of the fuel selector valves' positioning, switching fuel tanks required the pilot to turn his body 90 degrees to reach the valve. This created a natural tendency to extend one's right foot against the right rudder pedal to support oneself while turning in the seat, which caused the aircraft to yaw (nose right) and pitch up.

The mechanic said that he told Denver that the fuel sight gauges were visible only to the rear cockpit occupant. Denver had asked how much fuel was shown. He told Denver that there was "less than half in the right tank and less than a quarter in the left tank". He then provided Denver with an inspection mirror so he could look over his shoulder at the fuel gauges. The mirror was later recovered from the wreckage. Denver said that he would use the autopilot in flight to hold the airplane level while he turned the fuel selector valve. He turned down an offer to refuel the aircraft, saying that he would only be flying for about an hour.

The NTSB interviewed 20 witnesses about Denver's last flight. Six of them had seen the plane crash into the bay near Point Pinos. Four said the aircraft was originally heading west. Five said that they saw the plane in a steep bank, with four saying that the bank was to the right (north). Twelve described seeing the aircraft in a steep nose-down descent. Witnesses estimated the plane's altitude between 350 and 500 feet (110 and 150 m) when heading toward the shoreline. Eight said they heard a "pop" or "backfire" accompanied by a reduction in the engine noise level just before the plane crashed into the sea.

In addition to Denver's failing to refuel and his subsequent loss of control while attempting to switch fuel tanks, the NTSB determined other key factors that led to the accident. Foremost among these was his inadequate transition training on this type of aircraft and the builder's decision to put the fuel selector handle in a hard-to-reach place. The board issued recommendations on the requirement and enforcement of mandatory training standards for pilots operating home-built aircraft. It also emphasized the importance of mandatory ease of access to all controls, including fuel selectors and fuel gauges, in all aircraft.