Aviation accident of an Omega Air Boeing 707 in 1990 - Flugunfall einer Boeing 707 der Omega Air 1990
The air accident of a Boeing 707 of Air Omega took place on 20 September 1990, when a Boeing 707-321B discarded that their last flight to cannibalizing on the Davis-Monthan Air Force Base in Tucson , Arizona was to start, at the start of Pinal Airpark crashed.  Two people were killed in the accident. In the course of the aircraft accident investigation, it turned out that the aircraft involved in the accident had already been partially dismantled and was not airworthy.
The operator Omega Air Inc. was a company founded by the brothers Ulick and Desmond McEvaddy in 1980 and specialized in trading in aircraft fuselages and spare parts for the Boeing 707. The company was finally merged into Omega Aerial Refueling Services in 2001 .
The Boeing 707-321B, which was to be used for the transfer flight, was part of a larger batch of discarded Boeing 707 and Boeing 720 machines that the United States Air Force had bought. In particular, the engines and engine pylons should continue to be used for machines of the United States Air Force (USAF). The background was that after its production as a civil airliner was discontinued, this type of aircraft had been built as a military aircraft for many years until 1991 and was operated in large numbers by the United States Air Force and the USAF had stocks of spare parts for those in operation Machines created. 
When used machine, there was a discarded Boeing 707-321B that as 783. Machine Series 707/720 with serial number 20028 was manufactured and on 6 February 1969 with the aircraft marks N891PA and the name Clipper Gem of the Ocean for the first time the Pan American World Airways had been admitted. From August 1976 to June 1982 the Boeing was then operated by BWIA West Indies Airways and was then registered for three other owners before it was registered with Omega Air Inc. on September 8, 1990.  The four - engined long - range narrow-body aircraftwas four Turbojettriebwerken type Pratt & Whitney Jt3d-3 driven. The machine had a cumulative total operating performance of 34,965 operating hours.
A crew of three, consisting of the master, first officer and flight engineer, sat in the aircraft for the flight.  The 60-year-old captain, who was on the flight of Pilot Flying , had 13,192 hours of flight experience, of which he had completed around 4,000 in the cockpit of the Boeing 707.
Before the accident, the machine was parked at Pinal Airpark , an airport in the Arizona desert, which includes a disposal area for disused commercial aircraft and where machines are also cannibalized. The discarded passenger plane had been bought by Omega Air Inc. in the same month and was to be flown to Davis-Monthan Air Force Base to be dismantled by the 309th Aerospace Maintenance and Regeneration Group . The spare parts obtained in this way were intended for the maintenance of machines such as the Boeing KC-135 , Boeing C-135 , Northrop Grumman E-8 Joint STARS or the Boeing E-3 Sentrybe won. Since the two locations are only around 50 miles (approx. 80 kilometers) apart as the crow flies, only a short transfer flight of around 10 minutes was planned according to visual flight rules and well below the usual cruising altitude.
At the start of runway 12 shortly after take-off , the machine rolled to the right because the rudder was incorrectly adjusted. The plane went down and spun on its own axis, causing the fuselage to break apart. The flight captain was killed. 
Cause of accident
The investigation into the accident came to the conclusion that the master had probably worked through the checklist offhand and overlooked an incorrect rudder trim. In addition, the machine was basically handed over in a no longer airworthy condition: The cockpit was partially dismantled: around 50 displays and switches that were contractually available to other recycling companies had already been removed. Only two speed indicators, an altimeter and an artificial horizon were available as displays. The compass was missing, as was part of the checklists. The displays for the engine thrust (measured as Engine Pressure Ratio , EPR ) were only temporarily attached. 
In its final report, the NTSB gave the pilot responsibility for the accident on the one hand, as he had not used a checklist, but had also had little flight experience with this type of aircraft in recent times. In addition, the NTSB also criticized the commissioning of an obviously non-airworthy aircraft as well as insufficient monitoring of the process by the Federal Aviation Administration , especially since the machines were operated with a special permit. 
- Video of the original machine before the accident
- Peter Garrison: The last "ya-hoo", Flying Magazine, Okt. 1992, S. 110.
- 707 on Way to Plane Graveyard Crashes, Los Angeles Times, 21. September 1990.
- 707 Crashes En Route to Graveyard, Tulsa World, 21. September 1990.
- Accident report , National Transportation Safety Board , Jan. 15, 1992.
- Accident report B-707-300 N320MJ Aviation Safety Network (English), accessed on March 15, 2019.
- Operating history B-707-300, N320MJ jetphotos (English), accessed on March 15, 2019