Altitude deviation during descent in which the clearance is confusing.

Attributes
ACN	298660
Time
Date	199503
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : rbv
State Reference	NJ
Altitude	msl bound lower : 11000 msl bound upper : 12000
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	descent other
Route In Use	enroute airway : zdc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 4000
ASRS Report	298660
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

On descent, controller cleared us to 14000 ft pilot discretion to 10000 ft. At about 15 mi he said, 'change that to 12000 ft instead of 14000 ft.' we continued below 12-10 when he said, verify leveling at 12000 ft. We said we were pilot discretion to 10000 ft. He said no when I changed the clearance that eliminated the pd to 10000 ft. Later I apologized for the confusion. TCASII showed no conflict on our path for 20 mi. While we realize that 1 clearance can eliminate another this was confusing because it appeared he changed only 1 portion of the clearance.

Original NASA ASRS Text

Title: ALTDEV DURING DSCNT IN WHICH THE CLRNC IS CONFUSING.

Narrative: ON DSCNT, CTLR CLRED US TO 14000 FT PLT DISCRETION TO 10000 FT. AT ABOUT 15 MI HE SAID, 'CHANGE THAT TO 12000 FT INSTEAD OF 14000 FT.' WE CONTINUED BELOW 12-10 WHEN HE SAID, VERIFY LEVELING AT 12000 FT. WE SAID WE WERE PLT DISCRETION TO 10000 FT. HE SAID NO WHEN I CHANGED THE CLRNC THAT ELIMINATED THE PD TO 10000 FT. LATER I APOLOGIZED FOR THE CONFUSION. TCASII SHOWED NO CONFLICT ON OUR PATH FOR 20 MI. WHILE WE REALIZE THAT 1 CLRNC CAN ELIMINATE ANOTHER THIS WAS CONFUSING BECAUSE IT APPEARED HE CHANGED ONLY 1 PORTION OF THE CLRNC.

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.