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While the Oct. 14, 2004, crash of a Pinnacle Airlines [PNCL] regional jet illustrates how aircrews are not adequately protected against multi-engine flameout, and better training and recovery procedures may be in order, it remains to be determined what role the engine played in the fatal crash. After three days of hearings earlier this month by National Transportation Safety Board (NTSB) it was apparent that there may be flaws in the engine. However, the agency won't be issuing its recommendations for months.
In this second of two-parts, Regional Aviation News is examining the cause of the Pinnacle Flight 3701's crash. Last week, the report focused on the pilots' behavior and Pinnacle's changes to avoid similar accidents in the future. This report will focus on the General Electric [GE] engines on the Bombardier [BBD] CRJ 200. The engines apparently failed because the pilots pushed the plane and engines beyond the certified performance envelope. It remains to be determined if the engines failed to restart because of design or manufacturing problems or if they were simply pushed to hard.
The aircraft was on a positioning flight from Little Rock, Ark., to Minneapolis-St. Paul, Minn., when it crashed near Jefferson City Memorial Airport in Missouri around 10:15 p.m. after climbing to 41,000 feet and suffering a dual-engine flameout. As a non-revenue positioning flight, only the captain and first officer were aboard, and both were killed in the crash.
Because pilots slow and sharp approach to 41,000 feet, the engine core rotation speed, or N2, began to decrease, and the engines flamed out (trying to maintain the cleared height led to a drop in airspeed and axial flow through the engines). The captain declared an emergency.
The inexperience and lack of training may have played a role from here on out. For example, do you drift down initially to evaluate the situation? If you decide to do this, you initially decrease the airspeed to about 210 knots for a very leisurely descent. This low speed would probably cause the engine cores to stop rotating, and returning to windmilling speed would require giving up a great deal of altitude. The engines feature a 6.21 ratio (bypass to core engine airflow), so a very lackadaisical response from the N2 would...