Atx small aircraft on VOR approach in IMC begins descent to minimum altitude prior to reaching desce...

Attributes
ACN	127052
Time
Date	198910
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : smo
State Reference	CA
Altitude	msl bound lower : 900 msl bound upper : 1150
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : smo
Operator	common carrier : air taxi
Make Model Name	Small Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : air taxi
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 50 flight time total : 5000 flight time type : 1400
ASRS Report	127052
Person 2
Affiliation	company : air taxi
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	non adherence : published procedure other anomaly other other spatial deviation
Independent Detector	other controllera
Resolutory Action	flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We started down to minimums 1 mi before the final descent fix. It was caused by a misunderstanding of a nonstandard callout by the copilot. The captain understood that the aircraft was at the fix when the first officer made a 'mile to go' call. At 250' below the required altitude, the tower reported a low altitude warning. It was the second mission for this captain-first officer together. Much discussion of communication and procedures has resulted.

Original NASA ASRS Text

Title: ATX SMA ON VOR APCH IN IMC BEGINS DESCENT TO MINIMUM ALT PRIOR TO REACHING DESCENT FIX.

Narrative: WE STARTED DOWN TO MINIMUMS 1 MI BEFORE THE FINAL DSCNT FIX. IT WAS CAUSED BY A MISUNDERSTANDING OF A NONSTANDARD CALLOUT BY THE COPLT. THE CAPT UNDERSTOOD THAT THE ACFT WAS AT THE FIX WHEN THE FO MADE A 'MILE TO GO' CALL. AT 250' BELOW THE REQUIRED ALT, THE TWR REPORTED A LOW ALT WARNING. IT WAS THE SECOND MISSION FOR THIS CAPT-F/O TOGETHER. MUCH DISCUSSION OF COM AND PROCS HAS RESULTED.

Data retrieved from NASA's ASRS site as of August 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.

Atx small aircraft on VOR approach in IMC begins descent to minimum altitude prior to reaching descent fix.