Pan Am Flight 845

The Boeing 747-121, registration N747PA, manufacturer's serial number 19639, first flew on April 11, 1969 and was delivered to Pan Am on October 3, 1970. It was the second 747 off Boeing's production line but was delivered nearly ten months after Pan Am's first 747 flight. Originally named Clipper America, it had logged 2,900 hours of operation at the time of the accident.{{cite web |title=Boeing 747 complete production list |url=http://www.airfleets.net/listing/b747-1.htm |accessdate=2009-06-30 |website=airfleets.net}}

The flight crew of Flight 845 consisted of five (a captain, a first officer, a flight engineer, a relief flight engineer, and a relief pilot). The captain was Calvin Y. Dyer, a 57-year-old resident of Redwood City, California, a pilot with 27,209 hours of flying experience, 868 of which were on the 747. The first officer was Paul E. Oakes, a 40-year-old resident of Reno, Nevada, with 10,568 hours of experience, 595 on the 747. The flight engineer was Winfree Horne, who was 57 years old and from Los Altos, California, and had 23,569 hours of flight experience, 168 of them on the 747. The 34-year-old second officer, Wayne E. Sagar, was the relief pilot and had 3,230 hours of flight experience, 456 of them on the 747. The relief flight engineer was Roderic E. Proctor, a 57-year-old resident of Palo Alto, California, who had 24,576 flight hours, 236 of them on the 747.

On July 29, 1971, Dyer, Oakes, Horne, Sagar and Proctor had spent the whole day off-duty and had flown the initial Los Angeles to San Francisco leg of the flight.

File:KSFO Airport Diagram.png

Flight 845's crew had planned and calculated its takeoff for runway 28L but discovered only after pushback that this runway had been closed hours earlier for maintenance,Crews were repairing a crack, which had appeared in the pavement that morning. and that the first {{convert|1000|ft|m}} of runway 01R, the preferential runway at that time,{{efn|For noise abatement.}} had also been closed. After consulting with Pan Am flight dispatchers and the control tower, the crew decided to take off from runway 01R, shorter than 28L, with less favorable wind conditions.Runway 28L was {{convert|10600|ft|m}} long, and the wind was from the west at {{convert|22|kn|km/h}}. (See NTSB report, p. 10.)

Runway 01R was about {{convert|8500|ft|m}} long from its displaced threshold (from which point the takeoff was to start) to the end, which was the available takeoff length for Flight 845.Boeing 747 aircraft were not authorized to apply takeoff thrust before reaching the displaced threshold of runway 01R to reduce jetblast effects on a nearby highway (see NTSB report). Because of various misunderstandings, the flight crew was erroneously informed that the available takeoff length from the displaced threshold was {{convert|9500|ft|m}}, or {{convert|1000|ft|||}} longer than actually existed. Despite the shorter length, it was later determined that the aircraft could have taken off safely if the proper procedures had been followed.

As the crew prepared for takeoff on the shorter runway, it selected 20 degrees of flaps, instead of the originally-planned 10 degree setting, but did not recalculate the takeoff reference speeds (V₁, V_r and V₂), which had been calculated for the lesser flap setting and were thus too high for their actual takeoff configuration.

Consequently, the critical speeds were achieved late and the aircraft's takeoff roll was abnormally prolonged. In fact, the first officer called V_r at {{convert|160|kn|mph km/h|0}}, instead of the planned {{convert|164|kn|mph km/h|0}}, because the end of the runway was "coming up at a very rapid speed."The most critical reference speed is V_r, which is when the pilot flying (pilot manipulating the controls, in this flight the captain) "rotates" (lifts the aircraft's nose). If rotation is done too late in the takeoff roll, the climb will be delayed and the obstruction clearance reduced.

File:Pan Am Flight 845 damage.png structures (from NTSB final report).]]{{External media|float=|width=|video1={{YouTube|id=3lAhryBHxvM|title=Various angles of the incident}}|video2={{YouTube|id=x6iDVIVuMPg|title=Amateur footage of the incident}}}}

Unable to attain sufficient altitude to clear obstructions at the end of the runway, the aircraft had its aft fuselage, landing gear, and other structures damaged as it struck components of the approach lighting system (ALS) at over {{convert|160|kn|mph km/h}}. Three lengths of angle iron up to {{convert|17|ft}} penetrated the cabin, injuring two passengers. The right main under-body landing gear was forced up and into the fuselage, and the left under-body landing gear was ripped loose and remained dangling beneath the aircraft. Other systems damaged in the impact included No. 1, 3, and 4 hydraulic systems, several wing and empennage control surfaces and their mechanisms, electrical systems including the antiskid control, and three of the evacuation slides.

The flight proceeded out over the Pacific Ocean for 1 hour and 42 minutes to dump fuel to reduce weight for an emergency landing. During that time, damage to the aircraft was assessed, and the injured were treated by doctors on the passenger list. After dumping fuel, the aircraft returned to the airport. Emergency services were deployed, and the plane landed on runway 28L. During landing, six tires on the under-wing landing gear failed. Reverse thrust functioned only on engine 4 and so the aircraft slowly veered to the right, off the runway, and came to a stop. The left under-wing landing gear caught fire, but the fire was extinguished by dirt once the plane veered off the runway.{{Cite web|url=https://www.youtube.com/watch?v=tl_wXfSwRzM|title = Pan Am B747 San Francisco Accident 1971|website = YouTube| date=17 May 2013 }} After stopping, the aircraft slowly tilted backwards because the body gear had been ripped off or disabled on takeoff. The aircraft came to rest on its tail with its nose elevated. Until the accident, it was not known that the 747 would tilt backwards without the support of the main body gear.

There were no fatalities among the 218 passengers and crew aboard, but 2 passengers were seriously injured during the impact, and during the subsequent emergency evacuation, 27 more sustained injuries, 2 of them seriously.

Rods of angle iron from the ALS structure penetrated the passenger compartment, injuring passengers in seats 47G (near-amputation of left leg below the knee) and 48G (severe laceration and crushing of left upper arm).

After landing, the aircraft veered off the runway on its damaged landing gear and came to a halt. Evacuation commenced from the front because the evacuation order was not broadcast over the cabin address system (it was erroneously broadcast over the radio), the order being given by one of the flight crew exiting the cockpit and noticing that evacuation had not commenced. During that time, the aircraft settled aft, resting on its tail in a nose-up attitude. The four forward slides were unsafe for use because of the greater elevation and high winds. Most passengers evacuated from the rear six slides. Eight passengers using the forward slides sustained serious back injuries and were hospitalised. Other passengers suffered minor injuries such as abrasions and sprains.

The accident was investigated by the National Transportation Safety Board (NTSB), which issued its final report on May 24, 1972. The NTSB found the probable cause of the accident:{{cite web |title=ASN accident record |url=http://aviation-safety.net/database/record.php?id=19710730-2 |accessdate=2009-06-30 |website=Aviation Safety Network |publisher=Flight Safety Foundation}}

...the pilot's use of incorrect takeoff reference speeds. This resulted from a series of irregularities involving: (1) the collection and dissemination of airport information; (2) aircraft dispatching; and (3) crew management and discipline; which collectively rendered ineffective the air carrier's operational control system.

File:Boeing 747-121(A-SF), Pan American World Airways - Pan Am AN0147037.jpg in 1989]]

After the accident, the aircraft was repaired and returned to service. N747PA was re-registered and leased to Air Zaïre as N747QC from 1973 to March 1975, when it was returned to Pan Am, and it was renamed Clipper Sea Lark and then Clipper Juan T. Trippe in honor of the airline's founder. It remained with Pan Am until the airline ceased operations in 1991 and was transferred to Aeropostal and then briefly to Kabo Air of Nigeria and back to Aeroposta, and it was finally cut into pieces in 1999 at Norton AFB in San Bernardino, California, where it had been stored since at least 1997.

File:Boeing 747 Restaurant Outside.jpg, South Korea, where it was converted into a restaurant.]]

The parts of the aircraft were shipped to Hopyeong, Namyangju, South Korea, and reassembled to serve as a restaurant for some time until it closed down. Petitions and campaigns from numerous aviation enthusiasts for museums or local governments then occurred to preserve the historical airplane. The aircraft was scrapped in 2010.{{cite web|last=|first=|title=Aeroposta N747PA (ex N747QC)|url=http://www.airfleets.net/ficheapp/plane-b747-19639.htm|publisher=Airfleets|doi=|authorlink=|accessdate=}}

{{cite web|title=Picture of the Boeing 747-121 aircraft|url=http://www.airliners.net/photo/Boeing-747-121/1471902/%26sid%3Dbedfade942d0fe487f6c505821469f3f|publisher=Airliners.net|accessdate=2009-06-30|archive-date=2016-06-07|archive-url=https://web.archive.org/web/20160607133808/http://www.airliners.net/photo/Boeing-747-121/1471902/%26sid%3Dbedfade942d0fe487f6c505821469f3f|url-status=dead}}{{cite web|title=N747PA rusting away|url=https://www.pprune.org/jet-blast/370996-n747pa-rusting-away.html|publisher=PPRuNe|accessdate=2009-06-30}}{{Cite news|last=Glionna|first=John M.|date=2010-12-13|title=Historic 747 reaches grim end in South Korea|language=en-US|work=Los Angeles Times|url=https://www.latimes.com/archives/la-xpm-2010-dec-13-la-fg-korea-plane-demolition-20101213-story.html|access-date=2018-02-17|issn=0458-3035}}{{Cite web|title=카카오맵|url=https://map.kakao.com/?panoid=1081098630&pan=104.4&tilt=-6.9&zoom=-1&map_type=TYPE_SKYVIEW&map_hybrid=true&map_attribute=ROADVIEW&q=%ED%8F%89%EB%82%B4%ED%98%B8%ED%8F%89%EC%97%AD&urlX=555168&urlY=1154075&urlLevel=3|access-date=2021-08-03|website=카카오맵|language=ko}}

In 2017, Airways Magazine made an article claiming that N747PA had only partially been scrapped and that three major pieces of fuselage were saved and moved not far away to the suburb of Wolmuncheon-ro. The former aircraft was then reported to be used as a church in a Korean Air livery. (Location:1052-7 Wolmun-ri, Wabu-eup, Namyangju-si, Gyeonggi-do, South Korea).{{Cite web|last=Diamond|first=Cody|date=2017-12-03|title=Finding the Clipper Juan T. Trippe – In 2017|url=https://airwaysmag.com/avgeek/finding-the-clipper-juan-trippe/|access-date=2021-01-15|website=Airways Magazine|language=en-US|archive-date=2021-01-19|archive-url=https://web.archive.org/web/20210119180356/https://airwaysmag.com/avgeek/finding-the-clipper-juan-trippe/|url-status=dead}} However, the claim was proven false as the 747 claimed to be N747PA, had been there long before the aircraft had been scrapped. As of 2020, the unknown church 747 had been removed as well and replaced by a new building.{{Cite web|date=2018-07-10|title=[Cityscapes] Searching for lost jumbo jets in Korea|url=https://www.koreatimes.co.kr/www/nation/2021/08/177_252050.html|access-date=2021-08-03|website=koreatimes|language=en}}{{Citation|title=N747PA - The Story of the 2nd 747 Built| date=30 July 2021 |url=https://www.youtube.com/watch?v=awXZRQlTZaU|language=en|access-date=2021-08-03}}{{Cite web |title=카카오맵 |trans-title=Kakao Map |url=https://map.kakao.com/?panoid=1080937024&pan=142.3&tilt=-3.4&zoom=2&map_type=TYPE_SKYVIEW&map_hybrid=true&map_attribute=ROADVIEW&q=%EA%B2%BD%EA%B8%B0+%EB%82%A8%EC%96%91%EC%A3%BC%EC%8B%9C+%EC%99%80%EB%B6%80%EC%9D%8D+%EC%9B%94%EB%AC%B8%EB%A6%AC+1052-15&urlX=55 |access-date=2021-08-03 |website=Kakao Map |language=ko}}

• N747PA, the aircraft involved in the accident
• Emirates Flight 407
• MK Airlines Flight 1602, an almost identical accident involving a Boeing 747 which occurred 33 years later, albeit with fatalities
• List of accidents and incidents involving commercial aircraft

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{{reflist|2}}

• [https://web.archive.org/web/20071201041643/http://www.panamair.org/accidents/accidents.htm Entry in a list of Pan Am accidents 1932–1988]
• {{YouTube|id=tl_wXfSwRzM|title=Pan Am B747 San Francisco Accident 1971}} – video and analysis of the accident
• [http://www.airliners.net/photo/Pan-Am/Boeing-747-121(A-SF)/1474675/L/ Photo of accident aircraft N747PA on airliners.net]
• [http://www.airlinercafe.com/page.php?id=77 Photos of damaged N747PA and memoirs of hangar employee] {{Webarchive|url=https://web.archive.org/web/20191205001401/http://www.airlinercafe.com/page.php?id=77 |date=2019-12-05 }}
• [https://www.youtube.com/watch?v=awXZRQlTZaU Video on the history of the accident aircraft.]

{{Pan Am}}

{{Aviation accidents and incidents in 1971}}

{{Aviation accidents and incidents in the United States in the 1970s}}

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845

Category:Aviation accidents and incidents in the United States in 1971

Category:Airliner accidents and incidents caused by pilot error

Category:Airliner accidents and incidents in California

Category:History of San Mateo County, California

Category:1971 in California

Category:July 1971 in the United States

Category:San Francisco International Airport

Category:Accidents and incidents involving the Boeing 747