Pacific Southwest Airlines Flight 182

Pacific Southwest Airlines (PSA) Flight 182, registration N533PS, was a Boeing 727-214 commercial airliner that collided with a private Cessna 172 over San Diego, California on September 25, 1978. It was Pacific Southwest Airlines' first accident involving fatalities. The death toll of 144 makes it the deadliest aircraft disaster in California history. It was also the deadliest plane crash in the history of the United States until American Airlines Flight 191 went down eight months later.

Both aircraft crashed into North Park, a San Diego neighborhood, killing all 135 on board the Boeing, the two men aboard the Cessna, and seven people on the ground, including two children. Nine others on the ground were injured and 22 homes were destroyed or damaged. The midair collision contributed to San Diego's Lindbergh Field airport being ranked 10th among the world's Most Extreme Airports in a two-hour documentary of the same name released in July 2010, which aired in the U.S. on the History Channel. The PSA 182 accident caused the revision of air traffic rules applicable to the busiest airports across the U.S., with the intention of improving separation of aircraft operating in the vicinity of large airports.

Accident
Pacific Southwest Airlines flight 182 was a popular early-morning commuter flight terminating at San Diego's Lindbergh Field. The flight originated in Sacramento on Monday, September 25, 1978, with a stopover in Los Angeles. At the controls were Captain James E. McFeron (with over 10,000 hours flying time in the B-727), co-pilot Robert E. Fox, and flight engineer Martin J. Wahne.

As they neared the end of their flight in full sunlight and clear weather conditions, with visibility extending 10 miles (16 km), the PSA crew was alerted by the approach controller about a small Cessna aircraft nearby. The Cessna was being flown by two licensed pilots. One was 32-year-old Martin B. Kazy Jr., who possessed single-engine, multi-engine and instrument flight ratings, as well as a commercial certificate and an instrument flight instructor certificate. The other, 35-year-old David Boswell, a U.S. Marine Corps sergeant, possessed single-engine and multi-engine ratings and a commercial certificate and was at the time of the accident practicing ILS approaches under the instruction of Kazy in pursuit of his instrument rating. They had departed from Montgomery Field, and were navigating under VFR, which did not require the filing of a flight plan. Boswell was wearing a "hood" to limit his field of vision straight ahead to the cockpit panel, much like an oversize sun visor with vertical panels to block peripheral vision, as is normal in IFR training.

The PSA pilots reported that they saw the Cessna after being notified of its position by ATC, although cockpit voice recordings revealed that shortly thereafter the PSA pilots no longer had the Cessna in sight and they were speculating about its position. Lindbergh tower heard the 09.00:50 transmission as "He's passing off to our right" and assumed the PSA jet had the Cessna in sight.

After getting permission to land, and about 40 seconds before colliding with the Cessna, the conversation among the four occupants of the cockpit (captain, first officer, flight engineer and the off-duty PSA captain, Spencer Nelson, who was riding in the cockpit's jump seat) was as follows, showing the confusion:

Actually, the Cessna was directly in front of and below the Boeing, and the PSA jet was descending and rapidly closing in on the small plane, which had taken a right turn to the east, deviating from the assigned course. According to the report issued by the National Transportation Safety Board (NTSB), the Cessna may have been a difficult visual target for the jet's pilots, as it was below them and blended in with the multicolored hues of the residential area beneath, and the apparent motion of the Cessna as viewed from the Boeing was minimized as both planes were on approximately the same course. The report said that another possible reason that the PSA aircrew had difficulty observing the Cessna was that its fuselage was made visually smaller due to foreshortening. However, the same report in another section also stated that "the white surface of the Cessna's wing could have presented a relatively bright target in the sunlight."

A visibility study cited in the NTSB report concluded that the Cessna should have been almost centered in the windshield of the Boeing from 170 to 90 seconds before the collision, and thereafter it was likely positioned on the lower portion of the windshield just above the windshield wipers. The study also said that the Cessna pilot would have had about a 10-second view of the Boeing from the left-door window about 90 seconds before the collision, but visibility of the overtaking jet was blocked by the Cessna's ceiling structure for the remainder of the time.

Flight 182's crew never explicitly alerted the tower that they had lost sight of the Cessna. If they had made this clear to controllers, the crash might not have happened. Also, if the Cessna had maintained the heading of 70 degrees assigned to it by ATC instead of turning to 90 degrees, the NTSB estimates the planes would have missed each other by about 1000 feet (305 meters) instead of colliding. Ultimately, the NTSB maintained that regardless of that change in course, it was the responsibility of the crew in the overtaking jet to comply with the regulatory requirement to pass "well clear" of the Cessna.

Approach Control on the ground picked up an automated conflict alert 19 seconds before the collision but did not relay this information to the aircraft because, according to the approach coordinator, such alerts were commonplace even when there was no actual conflict. The NTSB stated: "Based on all information available to him, he decided that the crew of Flight 182 were complying with their visual separation clearance; that they were accomplishing an overtake maneuver within the separation parameters of the conflict alert computer; and that, therefore, no conflict existed."

This was the conversation in the PSA cockpit starting 16 seconds prior to collision with the Cessna:

PSA Flight 182 overtook the Cessna, which was directly below it, both approximately on a 090 (due east) heading. The collision occurred at approximately 2,600 feet (790 m) and broke the Cessna, and the 727's right wing and empennage, to pieces. According to several witnesses on the ground, there was first a loud metallic "crunching" sound, then an explosion and fire that drew them to look up.

Staff photographer Hans Wendt of the San Diego County Public Relations Office was attending an outdoor press event with a still camera, and was able to take two post-collision photographs of the falling Boeing. Cameraman Steve Howell from local TV channel 39 was attending the same event, and captured the Cessna on film as it fell to earth. For its coverage of the disaster, The San Diego Evening Tribune, a predecessor to The San Diego Union-Tribune, was awarded a Pulitzer Prize in 1979 for "Local, General, or Spot News Reporting.

The wreckage of the Cessna plummeted to the ground, its vertical stabilizer torn from its fuselage and bent leftward, its debris hitting around 3,500 feet (1,100 m) northwest of where the 727 went down. PSA 182's right wing was heavily damaged, rendering the plane uncontrollable and sending it careening into a sharp right bank (clearly seen in the Wendt photos), and the fuel tank inside it ruptured and started a fire, when this final conversation took place inside the cockpit:

Flight 182 struck the ground 4830 meters (three miles) northeast of Lindbergh Field, in a residential section of San Diego known as North Park. It impacted in a high-speed, nose-down attitude while banked 50° to the right. Seismographic readings indicated that the impact occurred at 09:02:07, about 2.5 seconds after the cockpit voice recorder lost power. The jet impacted just west of the I-805 freeway, approximately nine meters (30 feet) north of the intersection of Dwight and Nile streets, with the bulk of the debris field spreading in a northeast to southwesterly direction towards Boundary Street. The coordinates for the Boeing crash site are 32°44′37″N 117°07′14″W. The largest piece of the Cessna impacted about six blocks away near 32nd St. and Polk Ave. The explosion and fire created a mushroom cloud that could be seen for miles, and first responders on the scene reported that there was nothing left but utter destruction.

In total, 144 people lost their lives in the disaster, including Flight 182's seven crew members, 30 additional PSA employees deadheading to PSA's San Diego base, the two Cessna occupants, and seven residents (five women, two male children) on the ground. Among the victims on board PSA Flight 182 were Alan Tetelman, professor of metallurgy at UCLA and president of Failure Analysis Associates (now Exponent), who was en route to investigate a U.S. Navy helicopter crash; Charles Dunsmoor Bren, the 34-year-old son of actress Claire Trevor Bren; Richard "Ric" Horne, the 51-year-old brother of American mezzo-soprano opera singer Marilyn Horne; and Valerie Woods Kantor, the first wife of future United States Secretary of Commerce Mickey Kantor. An additional nine people on the ground were injured, and 22 homes across a four-block area were destroyed or damaged. One passenger, Jack Ridout, a survivor of the Tenerife airport disaster the year before had also booked a ticket on Flight 182 from Los Angeles, but had cancelled his booking to leave for home the day before.

At the time it was the U.S.'s deadliest commercial air disaster, and it remains the worst in California's history.

At nearby St. Augustine High School (San Diego, California), a triage and command and control center was established, with its gymnasium being used as a makeshift morgue and for forensic investigation. Freezer units were used to preserve the biological remains, as San Diego was recording unusually high 100-degree temperatures at the time.

Investigation
The National Transportation Safety Board report (report number NTSB/AAR-79-05; released: 19-APR-1979) determined that the probable cause of the accident was the failure of the PSA flight crew to follow proper air traffic control (ATC) procedures. Flight 182's crew lost sight of the Cessna in contravention of the ATC's instructions to "keep visual separation from that traffic", and did not alert ATC that they had lost sight of it. Errors on the part of ATC were also named as contributing factors, including the use of visual separation procedures when radar clearances were available. Additionally the Cessna pilots, for reasons unknown, did not maintain their assigned east-northeasterly heading of 070 degrees after completing a practice instrument approach, nor did they notify ATC of their course change. Concerning this the NTSB report states, "According to the testimony of the controllers and the assistant chief flight instructor of the Gibbs Flite Center (owner of the Cessna), the 08:59:56 transmission from approach control to the Cessna only imposed an altitude limitation on the pilot, he was not required to maintain the 070° heading. However, the assistant chief flight instructor testified that he would expect the [Cessna] pilot to fly the assigned heading or inform the controller that he was not able to do so."

A dissenting opinion in the NTSB crash report by member Francis H. McAdams strongly questioned why the unauthorized change in course by the Cessna was not specifically cited as a "contributing factor" in the final report; instead, it was listed as simply a "finding", which carries less weight. McAdams also "sharply disagreed" with the majority of the panel on other issues, giving more weight to inadequate ATC procedures as another "probable cause" to the accident, rather than merely treating them as a contributing factor. McAdams also added the "possible misidentification of the Cessna by the PSA aircrew due to the presence of a third unknown aircraft in the area" as a contributing factor. The majority panel members did not cite this as a credible possibility. In an August 1982 amendment to the probable cause finding, the NTSB adopted McAdams’ viewpoints regarding both ATC and pilot failings.

Aftermath
In the aftermath of the devastation on the ground, a controversy renewed in San Diego over the placement of such a busy airport in a heavily populated area. Despite proposals to relocate it, San Diego International Airport, the busiest single-runway commercial airport in the U.S., remains in use.

As a result of the crash, the NTSB recommended the immediate implementation of a Terminal Radar Service Area around Lindbergh Field to provide for the separation of aircraft, as well as an immediate review of control procedures for all busy terminal areas. However, this initial rule did not include small general aviation aircraft. Therefore, on May 15, 1980, the Federal Aviation Administration (FAA), implemented what is called Class B airspace to provide for the separation of all aircraft operating in the area. Additionally, all aircraft, regardless of size, are required to operate under "positive radar control," a rule that allows only radar control from the ground for all aircraft operating in the airport's airspace.

At the time of the crash, Lindbergh Field was the only airport in San Diego County with an Instrument Landing System. As a direct result of the accident, the FAA quickly installed the system at Montgomery and Gillespie fields, and at McClellan-Palomar Airport.

As a result of this and other mid-air collisions, the "Traffic Collision Alert and Avoidance System" (TCAS) is now installed in all commercial passenger aircraft and in most commercial cargo airplanes. It not only gives the pilots visual and audible warnings in the cockpit when two aircraft are approaching each other, but even goes so far as to direct pilots to either climb or descend to avoid the other aircraft.

Because the PSA 182/Cessna collision was the result of pilot error, it is used as a teaching aid in modern flight training. Some flight schools use the crash in "human factors" classes, others refer to it while teaching airspace or visual separation rules.

Memorials
A memorial plaque honoring those who died on both planes and on the ground is located in the San Diego Aerospace Museum, near the Theodore Gildred Flight Rotunda in San Diego's Balboa Park. On the 20th anniversary of the crash, a tree was planted next to the North Park branch library, and a memorial plaque was dedicated to those who lost their lives. The library is not in the immediate vicinity of the actual crash site, which is completely rebuilt and bears no visible evidence of the crash.

On September 25, 2008, over 100 relatives and friends of the victims of PSA 182 gathered at Dwight and Nile streets in North Park for a 30th anniversary memorial of that fateful day.

Prior telemovie
In a case of life imitating art, the NBC telemovie Emergency!: Survival on Charter #220 (effectively a two-hour Emergency! episode filmed after the show was no longer a weekly series) had aired in March 1978, six months before the accident involving PSA Flight 182. It detailed the accidental daytime mid-air collision of a Douglas DC-8 airliner and a much smaller two-person aircraft and the resulting crash and carnage in a residential area of Los Angeles County.