Wednesday, January 13, 2010
"Miracle-on-the-Hudson" - IT DIDN'T HAVE TO HAPPEN!!!
OK, this is all SUPPOSITION, as I flew only Boeing 737 series (300-900) during my airline career. I know that Airbus aircraft utilize "Fly-by-Wire" aircraft controls (ailerons, elevator and rudder) as well as "Throttle-by Wire" engine thrust/power controls. The throttle/thrust levers on a Boeing are connected directly to the Engine Fuel Control -- move the throttle levers forward; more fuel goes to the engine, delivering more thrust (power). On an Airbus, move the throttle forward; the increased thrust/power demand goes by wire to the engine FADEC - Full Authority Digital Engine Control (A COMPUTER ATTACHED TO THE ENGINE FUEL CONTROL); if the Pilot's power/thrust demand is 'reasonable' for the flight conditions, determined by the FADEC from a multitude if sensor inputs, then increased fuel is fed to the engine then the Pilot's demand is satisfied and thrust increases.
SUPPOSE, just suppose a flock of Canadian Geese flies into both engines. Many of the sensors feeding the engine FADEC are knocked out and/or begin to provide questionable data to the FADEC. The FADEC's "firmware/software" will not allow the engine to exceed pre-programmed limitations -- if an engine has flamed out, and the normal array of sensor information is NOT available, then the FADEC cannot assure a restart would remain within limitations AND IT (FADEC) DOES NOT ALLOW THE ENGINE TO RESTART/RELIGHT. If an engine is still running at idle (MINIMUM THRUST) to keep it within normal limitations (programmed in the FADEC) and more thrust is demanded by the Pilot in this EMERGENCY SITUATION -- the FADEC will not increase fuel to the engine because normal limitations may be exceeded -- the engine remains at idle EVEN THOUGH THE THROTTLE/THRUST LEVER MAY BE AT FULL POWER. You're at 10000 feet, with partial power Teterborough Airport is easily makeable -- Newark Int'l a strong possibility - WITH PARTIAL POWER !!! With NO POWER, we have "the Miracle on the Hudson." Capt Sullenberger and his First Officer and Flight Attendent Crew deserve every possible accolade and award that can be given and much, much more. AIRBUS, on the other hand, deserves to have every aircraft with a FADEC grounded until a FADEC OVERRIDE is certified and operational before EVER FLYING AGAIN !!!.
BTW, EMBRAER (the aircraft manufacturer in Brazil) 135/145 Regional Jets were Certified by the FAA with FADECs that would shut down an engine if limits were going to be exceeded by continued operation EVEN IF ONE ENGINE WAS OUT and the remaining engine was required for a safe landing !! It is my understanding the FAA forced a change to the FADEC firmware/software so that couldn't happen AFTER THE embraer RJs HAD BEEN FLYING FOR 4-5 YEARS. Think about it.
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