Training Workshop «DO160/ED14» - Jessica France ABD 100 1.2 Specificities of Sustained Engine Imbalance Edouard ZUNDEL Systems Qualification Engineer for Mechanical and Climatic aspects 1
FBO : Fan Blade Out HPC : High Power Condition Windmilling 2 2
Sustained engine imbalance steps HPC Windmilling Fan Blade Out Event engine blade failure is sufficient to cause the engine to spool down on its own. engine blade failure is not sufficient to cause the engine to spool down on its own. 30 000 ft RWY 0 ft Sustained Engine Imbalance (Windmilling) High Power Condition 3 3
Shock due to Fan Blade Out In case of Fan Blade Off, the engine, which is suddenly unbalanced by its blade loss, induces very high acceleration levels during a very short time (< 3s), until the engine has significantly decelerated to Windmilling regime. During this phase, failure of some systems in the aircraft (principally in the failed powerplant) should not affect the immediate flight safety nor the continued safe flight and landing. All the systems required for immediate flight safety should be designed to sustain the FBO case: Isolation of the failed engine. Fire detection and fire extinction. Structural integrity of pieces of equipment Limited to equipment mounted in power plant and pylon 4 4
High Power Condition The high power imbalance condition occurs immediately after blade failure but before the engine is shut down or otherwise spools down. This condition addresses losing less than a full fan blade which may not be sufficient to cause the engine to spool down on its own. This condition may last from several seconds to a few minutes. In some cases it has hampered the crew's ability to read instruments that may have aided in determining which engine was damaged An imbalance condition equivalent to 50 percent of one blade at cruise rotor speed considered to last for 20 seconds may be assumed. It should be shown that attitude, airspeed, and altimeter indications will withstand the vibratory environment of the high power condition and operate accurately in that environment. 5 5
Windmilling The windmillingcondition results after the engine is shut down but continues to rotate under aerodynamic forces. This condition may last until the aeroplanecompletes its diversion flight, which could be several hours. Diversion mission Accélération t Initial descent and Cruise Frequency band : 10-15 Hz for A380 17-22 Hz for A318 Duration : 160-170 min. Approach and landing Frequency band : 3-10 Hz for A380 6-17 Hz for A318 Duration : 10 20 min. 30 000 ft RWY 0 ft 6 6
Windmilling Qualification process Equipment qualification Acceleration levels computed on primary structure System requirement List of required equipment Amplification of supports Installation rules Rules to ensure uncoupling with Windmilling spectrum clamp Accelerometers L = pitch Specific requirement for pipes and bundles 7 7
Windmilling Test levels Amplification induced by equipment support shall be considered 30g 20g 10g 6g 4g 2g 1g Acceleration level (g) 8 8