1972 Lake Winnebago mid-air collision

Flight history

North Central Airlines Flight 290

North Central Airlines Flight 290 was a regularly scheduled flight which usually originated in Houghton, Michigan, and stopped at Ironwood, Michigan, and Green Bay, Oshkosh, and Milwaukee, Wisconsin, before terminating at Chicago, Illinois. On June 29, 1972, bad weather in northern Michigan necessitated cancellation of the Houghton-Ironwood and Ironwood-Green Bay legs, and the flight originated at Green Bay, using a replacement crew sent from Chicago to Green Bay.

The aircraft operating the flight, a Convair CV-580, departed Green Bay at around 10:30 a.m. CDT, proceeding to Oshkosh under visual flight rules (VFR). At 10:36:11 a.m. CDT, the air traffic controller at Oshkosh cleared Flight 290 to land. The flight crew's acknowledgment five seconds later was the last communication with North Central Flight 290.

Air Wisconsin Flight 671

Air Wisconsin Flight 671 was a regularly scheduled flight from Chicago, Illinois, to Appleton, Wisconsin, with a stopover at Sheboygan County Memorial Airport west of Sheboygan, Wisconsin. Operated by a de Havilland Canada DHC-6 Twin Otter, it departed Chicago at 9:28 a.m. CDT on June 29, 1972, bound for Sheboygan under an instrument flight rules (IFR) plan; en route, the flight crew abandoned its IFR plan and completed the first leg of the flight under VFR.

The plane departed Sheboygan 13 minutes late, at 10:23 a.m. CDT, bound for Appleton, operating under VFR. At about 10:30 a.m. CDT, the flight crew contacted the Air Wisconsin office in Appleton, stating that they anticipated arriving at Appleton at 10:44 a.m. CDT. This was the last communication with Air Wisconsin Flight 671.

Collision

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Operating in bright sunshine beneath a scattered cloud layer, Flights 290 and 671 collided at 10:36:47 a.m. CDT over Wisconsin's Lake Winnebago about 6 nmi south of Appleton and 2.5 nmi east of Neenah, Wisconsin, at an altitude of about 2,500 feet (762 m). The left wing of Flight 671 hit the left wing of Flight 290. The collision resulted in an explosion which tore off most of the Twin Otter's wing, and around a quarter of the CV-580's left wing. The collision left both aircraft uncontrollable resulting in both crashing into Lake Winnebago around 2 nmi east of Neenah Light.

The National Transportation Safety Board noted that the North Central crew would have had to look toward the sun to see the approaching Air Wisconsin plane and concluded that they took no evasive action. The rate of closure during the final five seconds before the collision was 688 ft/s.

Aircraft

The North Central aircraft involved, N50858, had been completed as a Convair CV-340/440 on May 25, 1953; it had later been converted to CV-580 standard. The Air Wisconsin Twin Otter had been completed on October 6, 1966. Both aircraft were destroyed by the collision and subsequent water impact. Their wreckage was found on the lake bottom scattered over an area roughly one mile (1.6 km) long by one-half mile (0.8 km) wide.

Casualties

The North Central plane had two passengers and a crew of three (Captain James Cuzzort, First Officer Alton Laabs, and Flight Attendant Frances Rabb) on board, while the Air Wisconsin flight was carrying six passengers and a crew of two (Captain David Jacobs and First Officer Michael Gaffin). All 13 people aboard the two planes died in the collision and subsequent crash, and the NTSB observed that the accident was not survivable.

Investigation

The National Transportation Safety Board released its report on the accident on April 25, 1973. It was "unable to determine why each crew failed to see and avoid the other aircraft," The report also noted that the decision by both flight crews to fly under VFR rather than IFR and the fact that neither captain requested in-flight advisories deprived both aircraft of air traffic control support, and that such support to even one of the aircraft would have ensured sufficient separation to avoid a collision.

The NTSB recommended that the Federal Aviation Administration create a standardized method for training and grading flight crews in visual search techniques and time-sharing between instrument checks and visual searches, and that the FAA expedite the development of anticollision systems.

References

Notes

Bibliography

• Aviation Safety Network: ASN Aircraft accident Convair CV-580 N90858 Appleton, WI
• National Transportation Safety Board Report Number NTSB-AAR-73-09 "Aircraft Accident Report North Central Airlines, Inc., Allison Convair 340/440 (CV-580), N90858, and Air Wisconsin, Inc., DHC-6, N4043B, Near Appleton, Wisconsin, June 29, 1972," adopted April 25, 1973

References

1. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
2. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
3. (September 20, 1972). "Witnesses describe June air crash". Milwaukee Journal.
4. Lubenow, Thomas G.. (June 30, 1972). "Why did 2 planes collide over lake?". Milwaukee Journal.
5. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
6. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
7. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
8. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
9. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].
10. (April 25, 1973). "NTSB Accident Report NTSB-AR-73-09". [[National Transportation Safety Board]].