Narrative:

Each pilot has over 2000 hours in falcon 50's, however, this was the second day of flying the new falcon 50EX after attending flight training for the new jet. The crew requested a descent from FL410 about 120 mi from its destination. The controller acknowledged the request but mentioned traffic would delay the clearance. A short time later the pilots understood the controller to have cleared them down to FL370. The PNF read back the descent to FL370, but pilots agreed to the altitude preselector being set to FL370 and both confirmed that the preselector was actually set to FL370. The vertical speed mode of the autoplt was selected and the vertical speed was slowly increased to 2000 FPM as thrust was reduced. Approaching FL390 and with no TCASII advisories, a glimpse of the mfd showed an aircraft 2200 ft below. The range to target was initially believed to be beyond 10 mi, but a closer look at the range marks showed the aircraft inside a 5 mi mark and we were passing FL390. Recognizing a potential conflict and questioning the assigned altitude, the PF reacted to arrest the descent by reaching for the autoplt pitch wheel as he glanced outside and immediately acquired the traffic. Unfortunately, the PF had reached for where the pitch wheel had been for over a decade and the descent continued while he reacted to his error and reached up to the current location and momentarily commanded over 6000 FPM up to regain the vertical separation required. The controller noticed us below FL390 and asked if we were level at FL390. The PNF responded honestly in the negative and both pilots were now aware by the controller's question that the controller had intended us to level at FL390. After the flight, the crew called the controller by phone. The controller had already listened to the tape. He had cleared us to FL390, not FL370, and the crew had read it back as FL370. The controller apologized and accepted responsibility for not having caught the readback. The crew, in turn, apologized and accepted responsibility for not hearing it correctly to begin with. Good communication skills continue to be of the utmost importance by all in our industry. New aircraft, or more correctly, new cockpits, although substantially improved, initially bring higher workloads causing distrs. This may have been a contributing factor in not hearing the clearance correctly. The crew actually caught the error by the good situational awareness provided by the new mfd with a TCASII overlay, however, reaction time, thus altitude lost, was unnecessarily extended because it is much more difficult to un-train pilots than it is to train them. In hindsight, it would have been easier and quicker to disconnect the autoplt to arrest the descent.

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Original NASA ASRS Text

Title: FA50 CREW DSNDED TOWARD AN OCCUPIED ALT AFTER READBACK HEARBACK PROBS IN ZLC CLASS A AIRSPACE.

Narrative: EACH PLT HAS OVER 2000 HRS IN FALCON 50'S, HOWEVER, THIS WAS THE SECOND DAY OF FLYING THE NEW FALCON 50EX AFTER ATTENDING FLT TRAINING FOR THE NEW JET. THE CREW REQUESTED A DSCNT FROM FL410 ABOUT 120 MI FROM ITS DEST. THE CTLR ACKNOWLEDGED THE REQUEST BUT MENTIONED TFC WOULD DELAY THE CLRNC. A SHORT TIME LATER THE PLTS UNDERSTOOD THE CTLR TO HAVE CLRED THEM DOWN TO FL370. THE PNF READ BACK THE DSCNT TO FL370, BUT PLTS AGREED TO THE ALT PRESELECTOR BEING SET TO FL370 AND BOTH CONFIRMED THAT THE PRESELECTOR WAS ACTUALLY SET TO FL370. THE VERT SPD MODE OF THE AUTOPLT WAS SELECTED AND THE VERT SPD WAS SLOWLY INCREASED TO 2000 FPM AS THRUST WAS REDUCED. APCHING FL390 AND WITH NO TCASII ADVISORIES, A GLIMPSE OF THE MFD SHOWED AN ACFT 2200 FT BELOW. THE RANGE TO TARGET WAS INITIALLY BELIEVED TO BE BEYOND 10 MI, BUT A CLOSER LOOK AT THE RANGE MARKS SHOWED THE ACFT INSIDE A 5 MI MARK AND WE WERE PASSING FL390. RECOGNIZING A POTENTIAL CONFLICT AND QUESTIONING THE ASSIGNED ALT, THE PF REACTED TO ARREST THE DSCNT BY REACHING FOR THE AUTOPLT PITCH WHEEL AS HE GLANCED OUTSIDE AND IMMEDIATELY ACQUIRED THE TFC. UNFORTUNATELY, THE PF HAD REACHED FOR WHERE THE PITCH WHEEL HAD BEEN FOR OVER A DECADE AND THE DSCNT CONTINUED WHILE HE REACTED TO HIS ERROR AND REACHED UP TO THE CURRENT LOCATION AND MOMENTARILY COMMANDED OVER 6000 FPM UP TO REGAIN THE VERT SEPARATION REQUIRED. THE CTLR NOTICED US BELOW FL390 AND ASKED IF WE WERE LEVEL AT FL390. THE PNF RESPONDED HONESTLY IN THE NEGATIVE AND BOTH PLTS WERE NOW AWARE BY THE CTLR'S QUESTION THAT THE CTLR HAD INTENDED US TO LEVEL AT FL390. AFTER THE FLT, THE CREW CALLED THE CTLR BY PHONE. THE CTLR HAD ALREADY LISTENED TO THE TAPE. HE HAD CLRED US TO FL390, NOT FL370, AND THE CREW HAD READ IT BACK AS FL370. THE CTLR APOLOGIZED AND ACCEPTED RESPONSIBILITY FOR NOT HAVING CAUGHT THE READBACK. THE CREW, IN TURN, APOLOGIZED AND ACCEPTED RESPONSIBILITY FOR NOT HEARING IT CORRECTLY TO BEGIN WITH. GOOD COM SKILLS CONTINUE TO BE OF THE UTMOST IMPORTANCE BY ALL IN OUR INDUSTRY. NEW ACFT, OR MORE CORRECTLY, NEW COCKPITS, ALTHOUGH SUBSTANTIALLY IMPROVED, INITIALLY BRING HIGHER WORKLOADS CAUSING DISTRS. THIS MAY HAVE BEEN A CONTRIBUTING FACTOR IN NOT HEARING THE CLRNC CORRECTLY. THE CREW ACTUALLY CAUGHT THE ERROR BY THE GOOD SITUATIONAL AWARENESS PROVIDED BY THE NEW MFD WITH A TCASII OVERLAY, HOWEVER, REACTION TIME, THUS ALT LOST, WAS UNNECESSARILY EXTENDED BECAUSE IT IS MUCH MORE DIFFICULT TO UN-TRAIN PLTS THAN IT IS TO TRAIN THEM. IN HINDSIGHT, IT WOULD HAVE BEEN EASIER AND QUICKER TO DISCONNECT THE AUTOPLT TO ARREST THE DSCNT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.