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12th of November 2003, Blog #573

After completing the necessary pre-flight activities, including refuelling the aircraft with 300 gallons of Jet A fuel with Prist, the two passengers boarded a Learjet 24D. (Prist is an anti-icing additive for Jet A Kerosine according to MIL-DTL-85470).

The burned-out wreckage (Source baaa-acro.com © Unknown)


Subsequently, the engines were started for a flight from Cahokia (Illinois, USA) to North Platte (Nebraska, USA). Weather conditions were good;

Wind - Variable at 5 knots

Clouds - none, sky clear

Temperature - 18 ºC Dew point - 16 ºC

Altimeter - 20.85 inHg


The aircraft taxied to runway 12R (6.997 feet long) and the takeoff checklist was completed, the V-speeds were set, and the flaps were selected to 10º. Once take-off clearance was received the throttles were forwarded and the aircraft accelerated down the runway. The standard calls were made as per standard operating procedures by the copilot during the take-off roll. And the aircraft was rotated at Vr (Rotation Speed). As the aircraft climbed out and accelerated to V2+30 the flaps were selected up. (V2 is the takeoff safety speed which must be attained at the 35 ft height at the end of the required runway distance. This is essentially the best one-engine inoperative angle of climb speed for the airplane and is a minimum speed for flight in that condition until at least 400 ft above the ground.) At that time the #2 engine (righthand) failed when it ingested several birds. (the co-pilot saw a flock of birds passing just off the nose, on the left-hand side of the aircraft). The captain immediately advanced the thrust lever for the #1 engine (left-hand engine) but noticed it was only at ~70% rpm, while the EGT was over the red line (above the limit) This short after take-off the aircraft was too low for a restart attempt or an immediate return to the field. The captain spotted a suitable area to crashland the aircraft and the aircraft touched down on the slope of a hill in a farm field. The wing tips were torn from the wings and the aircraft came to a stop. As the co-pilot assisted the passengers in evacuating the aircraft via the emergency exit, a fire was developing at the rear of the aircraft. The captain vacated the aircraft via the main exit and got away from the aircraft. Both crew members sustained light injuries, but the passengers escaped without any injury. The fire travelled through the aircraft and consumed the cabin and the cockpit, 95% of the aircraft was consumed by the fire. The local fire departments responded to the accident and extinguished the fire.

The burned-out wreckage (Source baaa-acro.com © Unknown)

The National Transportation Safety Board was alerted and an investigation was launched. A check of the CVR revealed that the pilot stated, "We hit a bird," and the copilot stating, "Yep," immediately following the CVR recording a "sound similar to decrease in engine RPM." The NTSB inspection of the airplane's fuel system, pneumatic system, engines, fuel controls and fuel pumps revealed no pre-impact anomaly. No physical evidence of bird ingestion was found in either engine. A CVR sound spectrum plot and a flight profile analysis revealed that one engine flamed out almost immediately after the sound of a "thump" on the CVR.


On the 13th of January, 2006, the NTSB published their report, in this report the National Transportation Safety Board stated that the probable cause(s) of this accident to be;

"The total loss of power to the right engine and the partial loss of power to the left engine after the airplane encountered a flock of birds during initial climb out, resulting in impeded ram induction airflow.


The NTSB report, which served as a source for this blog, can be accessed by clicking on the file below;

Learjet 24 engine failure 12-Nov-2003
.pdf
Download PDF • 139KB



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