Question: In what month was the crash that Dennis Nielsen is most widely known for having participated in the rescue effort for?

full_context: Document 1: Southwest Airlines Flight 1248: Southwest Airlines Flight 1248 (WN1248, SWA1248) was a scheduled passenger flight from Baltimore-Washington International Airport, in Baltimore, Maryland, to Chicago Midway International Airport, in Chicago, Illinois, to Salt Lake City International Airport in Salt Lake City, Utah, and then to McCarran International Airport in Las Vegas, Nevada. On December 8, 2005, the airplane slid off a runway at Chicago-Midway while landing in a snowstorm and crashed into automobile traffic, killing six-year-old Joshua Woods. This is the first, and so far, only accident involving Southwest Airlines to result in a fatality. It is also the first accident involving the airline to result in the death of someone not on the plane itself.
Document 2: Dennis Nielsen: Dennis Nielsen is a retired United States Air Force Colonel who is most widely known for having participated in rescue effort of the United Airlines Flight 232 crash in Sioux City, Iowa in 1989. Born in Shelby, Iowa, he has lived in the small town of Nashville, North Carolina since he retired from the Air National Guard in 2002.
Document 3: Chesley Sullenberger: Chesley Burnett "Sully" Sullenberger III (born 1951) is an American retired airline captain celebrated for the January 15, 2009 water landing of US Airways Flight 1549 in the Hudson River off Manhattan after the plane was disabled by striking a flock of Canada geese immediately after takeoff; all 155 people aboard survived. Sullenberger is an international speaker on airline safety and has helped develop new protocols for airline safety. He served as the co-chairman, along with First Officer Jeffrey Skiles, of the EAA's Young Eagles youth introduction-to-aviation program from 2009 to 2013. He retired from US Airways after 30 years as a commercial pilot on March 3, 2010. In May of the following year, Sullenberger was hired by CBS News as an Aviation and Safety Expert.
Document 4: Eugene Peyton Deatrick: Eugene Peyton Deatrick, Jr. (born November 17, 1924) is a retired United States Air Force colonel, test pilot, and combat veteran. He is best recognized for his role in the rescue of United States Navy Lieutenant Dieter Dengler during the Vietnam War. The rescue was recounted in the Werner Herzog films "Little Dieter Needs to Fly" and "Rescue Dawn" and the national bestseller "" by author Bruce Henderson.
Document 5: Dennis Byrd (American football, born 1946): Dennis Wayne Byrd (August 31, 1946 – July 22, 2010) was a defensive lineman who played one season in the American Football League for the Boston Patriots. He attended North Carolina State University, where he was an All-American. Byrd only played one season in the NFL because of a knee injury he suffered in his senior year at NC State. After leaving the NFL, Byrd became the high school football coach at West Lincoln High School in Lincolnton, North Carolina, retiring in 2004.
Document 6: Aloha Airlines Flight 243: Aloha Airlines Flight 243 (AQ 243, AAH 243) was a scheduled Aloha Airlines flight between Hilo and Honolulu in Hawaii. On April 28, 1988, a Boeing 737-297 serving the flight suffered extensive damage after an explosive decompression in flight, but was able to land safely at Kahului Airport on Maui. There was one fatality, flight attendant Clarabelle "C.B." Lansing, who was ejected from the airplane. Another 65 passengers and crew were injured. The safe landing of the aircraft despite the substantial damage inflicted by the decompression established Aloha Airlines Flight 243 as a significant event in the history of aviation, with far-reaching effects on aviation safety policies and procedures.
Document 7: Asiana Airlines Flight 214: Asiana Airlines Flight 214 was a scheduled transpacific passenger flight from Incheon International Airport near Seoul, South Korea, to San Francisco International Airport (SFO) in the United States. On the morning of Saturday, July 6, 2013, the Boeing 777-200ER crashed on final approach into SFO. Of the 307 people aboard, two passengers died at the crash scene, and a third died in a hospital several days later; all three of them were teenage Chinese girls. Another 187 individuals were injured, 49 of them seriously. Among the injured were four flight attendants who were thrown onto the runway while still strapped in their seats when the tail section broke off after striking the seawall short of the runway. It was the first crash of a Boeing 777 that resulted in fatalities since that aircraft model entered into service in 1995.
Document 8: Dana Air Flight 992: Dana Air Flight 992 was a scheduled domestic commercial passenger flight from Abuja to Lagos, Nigeria. On Sunday, 3 June 2012, the McDonnell Douglas MD-83 aircraft operating the flight crashed into a furniture works and printing press building in the Iju-Ishaga neighbourhood of Lagos. The crash resulted in the deaths of all 153 people on board and 10 more on the ground. The crash of Flight 992 is the deadliest aviation disaster involving a McDonnell Douglas MD-83, as well as the second-deadliest involving an MD-80 series aircraft, behind Inex-Adria Aviopromet Flight 1308. It is also the second-deadliest aircraft crash on Nigerian soil, behind the Kano air disaster of 1973.
Document 9: Swissair Flight 111: Swissair Flight 111 (ICAO: SWR111) was a scheduled international passenger flight from New York City, United States, to Geneva, Switzerland. This flight was also a codeshare flight with Delta Air Lines. On 2 September 1998, the McDonnell Douglas MD-11 performing this flight, registration HB-IWF, crashed into the Atlantic Ocean southwest of Halifax International Airport at the entrance to St. Margarets Bay, Nova Scotia. The crash site was 8 km from shore, roughly equidistant from the tiny fishing and tourist communities of Peggy's Cove and Bayswater. All 229 passengers and crew aboard the MD-11 died—the highest death toll of any McDonnell Douglas MD-11 accident in aviation history, and the second-highest of any air disaster to occur in Canada, after Arrow Air Flight 1285, which crashed in 1985 with 256 fatalities. This is one of the three MD-11 accidents with passenger fatalities along with China Eastern Airlines Flight 583 and another hull loss of China Airlines Flight 642.
Document 10: United Airlines Flight 811: United Airlines Flight 811 was a regularly scheduled airline flight from Los Angeles to Sydney, with intermediate stops at Honolulu, and Auckland. On February 24, 1989, the Boeing 747-122 serving the flight experienced a cargo door failure in flight shortly after leaving Honolulu. The resulting explosive decompression blew out several rows of seats, resulting in the deaths of nine passengers. The aircraft returned to Honolulu, where it landed safely.
Document 11: Sioux Falls Regional Airport: Sioux Falls Regional Airport (IATA: FSD, ICAO: KFSD, FAA LID: FSD) , also known as Joe Foss Field, is a public and military use airport owned by the Sioux Falls Regional Airport Authority and located three nautical miles (6 km) northwest of the central business district of Sioux Falls, a city in Minnehaha County, South Dakota, United States. Named in honor of aviator Joe Foss, it serves the greater Sioux Falls area, as well as communities throughout eastern South Dakota, southwestern Minnesota and northwestern Iowa.
Document 12: Delta Air Lines Flight 191: Delta Air Lines Flight 191 was a regularly scheduled Delta Air Lines domestic service from Fort Lauderdale, Florida, to Los Angeles, via Dallas that crashed on August 2, 1985, at 18:05 (). The Lockheed L-1011 TriStar operating this flight encountered a microburst while on approach to land on runway 17L (now marked 17C) at Dallas/Fort Worth International Airport (DFW). The pilots were unable to escape the weather event and the aircraft struck the ground over a mile short of the runway. The flight hit a car driving north of the airport and two water tanks, disintegrating. The crash killed 136 people on board, including 128 of the 152 passengers and 8 of the 11 crew, and the driver of the car. The National Transportation Safety Board (NTSB) determined that the crash resulted from the flight crew's decision to fly through a thunderstorm, the lack of procedures and training to avoid or escape microbursts, and the lack of hazard information on wind shear.
Document 13: Don Bacon (politician): Donald John Bacon (born August 16, 1963) is a retired United States Air Force Brigadier General and current U.S. Representative for Nebraska's 2nd congressional district.
Document 14: United Airlines Flight 232: United Airlines Flight 232 was a DC-10, registered as N1819U, that crash-landed at Sioux City, Iowa in July 19, 1989 after suffering catastrophic failure of its tail-mounted engine, which led to the loss of all flight controls. The flight was en route from Stapleton International Airport in Denver, Colorado to O'Hare International Airport in Chicago. Of the 296 passengers and crew on board, 111 died in the accident and 185 survived in total. Despite the deaths, the accident is considered a prime example of successful crew resource management due to the large number of survivors and the manner in which the flight crew handled the emergency and landed the airplane without conventional control.
Document 15: United Airlines Flight 608: United Airlines Flight 608 was a Douglas DC-6 airliner, registration NC37510, on a scheduled passenger flight from Los Angeles to Chicago when it crashed at 12:29 pm on October 24, 1947 about 1.5 miles southeast of Bryce Canyon Airport, Utah. There were no survivors among the 5 crew members and 47 passengers on board. It was the first crash of a DC-6, and at the time it was the second deadliest air crash in the United States, surpassed by Eastern Air Lines Flight 605 by only one fatality.
ground_truth: July