Narrative:

I was on #2 radio picking up sgf ATIS and calling company at destination, sgf. When I returned to #1 radio, ATC changed our descent clearance. Previously, we had pilot discretion descent from 20000 ft to approximately 8000 ft. PF had leveled off at 18000 ft, to remain on top of overcast. Now ATC requested we leave 18000 ft, then pilot discretion below 15000 ft (approximately). I read back 'out of 18,' however PF did not vacate 18000 ft right away. He waited approximately 80 seconds. He seemed to be waiting for a lowering in tops to appear, presumably to minimize turbulence. In meantime, ATC said we were 'still at 18000 ft on radar?' when he said that captain began descent out of 18000 ft. I, once again, said 'out of 18000 ft.' ATC, in angry tone, asked our altitude. I said 'passing 17800 ft.' rest of flight was uneventful. Although captain seemed nervous over ATC's reaction to his non- compliance. This captain was junior-manned for this leg only. I believe this had lowered his morale, hence performance. Normally, I read back descent clrncs by saying 'out of....for...altitude,' assuming PF is fixing to comply with clearance. In this case, there was no way for me to guess that he was not going to comply right away! In future, I will avoid saying 'out of certain altitude,' until I witness this taking place, unless I know the PF well.

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Original NASA ASRS Text

Title: A COMMUTER CAPT WAS SLOW TO INITIATE DSCNT TO COMPLY WITH CLRNC. A VERBAL EXCHANGE ENSUED BTWN THE FLC AND ATC.

Narrative: I WAS ON #2 RADIO PICKING UP SGF ATIS AND CALLING COMPANY AT DEST, SGF. WHEN I RETURNED TO #1 RADIO, ATC CHANGED OUR DSCNT CLRNC. PREVIOUSLY, WE HAD PLT DISCRETION DSCNT FROM 20000 FT TO APPROX 8000 FT. PF HAD LEVELED OFF AT 18000 FT, TO REMAIN ON TOP OF OVERCAST. NOW ATC REQUESTED WE LEAVE 18000 FT, THEN PLT DISCRETION BELOW 15000 FT (APPROX). I READ BACK 'OUT OF 18,' HOWEVER PF DID NOT VACATE 18000 FT RIGHT AWAY. HE WAITED APPROX 80 SECONDS. HE SEEMED TO BE WAITING FOR A LOWERING IN TOPS TO APPEAR, PRESUMABLY TO MINIMIZE TURB. IN MEANTIME, ATC SAID WE WERE 'STILL AT 18000 FT ON RADAR?' WHEN HE SAID THAT CAPT BEGAN DSCNT OUT OF 18000 FT. I, ONCE AGAIN, SAID 'OUT OF 18000 FT.' ATC, IN ANGRY TONE, ASKED OUR ALT. I SAID 'PASSING 17800 FT.' REST OF FLT WAS UNEVENTFUL. ALTHOUGH CAPT SEEMED NERVOUS OVER ATC'S REACTION TO HIS NON- COMPLIANCE. THIS CAPT WAS JUNIOR-MANNED FOR THIS LEG ONLY. I BELIEVE THIS HAD LOWERED HIS MORALE, HENCE PERFORMANCE. NORMALLY, I READ BACK DSCNT CLRNCS BY SAYING 'OUT OF....FOR...ALT,' ASSUMING PF IS FIXING TO COMPLY WITH CLRNC. IN THIS CASE, THERE WAS NO WAY FOR ME TO GUESS THAT HE WAS NOT GOING TO COMPLY RIGHT AWAY! IN FUTURE, I WILL AVOID SAYING 'OUT OF CERTAIN ALT,' UNTIL I WITNESS THIS TAKING PLACE, UNLESS I KNOW THE PF WELL.

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.