Instructor with student pilot descends below assigned when cleared for the approach.

Attributes
ACN	328310
Time
Date	199602
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : hqm
State Reference	WA
Altitude	msl bound lower : 3000 msl bound upper : 4000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zse tower : mci
Operator	general aviation : instructional
Make Model Name	Small Aircraft, High Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other descent other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time total : 3400
ASRS Report	328310
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : student
Events
Anomaly	non adherence : clearance non adherence : published procedure
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were 18 NM east of hqm VOR on V27 at 4000 ft when center cleared us for the VOR runway 06 approach at hqm. I then mistakenly instructed my student to begin a slow descent. We had descended to 3000 ft and were over the VOR when I realized my mistake. We intercepted the outbound course, and as we were now on a published segment, continued our descent, completed the approach and landed without further incident. I believe the reasons I made this mistake were two: the first was that I was concerned that we would need to lose 2400 ft while descending outbound over the ocean. The second was that I had become accustomed to receiving a clearance to descend from 4000 ft to 3000 ft doing many of the practice approachs in the area and 'heard' the descent along with the approach clearance. On debriefing I discussed my mistake with my student and emphasized to both of us the necessity to obtain verification when unsure of a clearance.

Original NASA ASRS Text

Title: INSTRUCTOR WITH STUDENT PLT DSNDS BELOW ASSIGNED WHEN CLRED FOR THE APCH.

Narrative: WE WERE 18 NM E OF HQM VOR ON V27 AT 4000 FT WHEN CTR CLRED US FOR THE VOR RWY 06 APCH AT HQM. I THEN MISTAKENLY INSTRUCTED MY STUDENT TO BEGIN A SLOW DSCNT. WE HAD DSNDED TO 3000 FT AND WERE OVER THE VOR WHEN I REALIZED MY MISTAKE. WE INTERCEPTED THE OUTBOUND COURSE, AND AS WE WERE NOW ON A PUBLISHED SEGMENT, CONTINUED OUR DSCNT, COMPLETED THE APCH AND LANDED WITHOUT FURTHER INCIDENT. I BELIEVE THE REASONS I MADE THIS MISTAKE WERE TWO: THE FIRST WAS THAT I WAS CONCERNED THAT WE WOULD NEED TO LOSE 2400 FT WHILE DSNDING OUTBOUND OVER THE OCEAN. THE SECOND WAS THAT I HAD BECOME ACCUSTOMED TO RECEIVING A CLRNC TO DSND FROM 4000 FT TO 3000 FT DOING MANY OF THE PRACTICE APCHS IN THE AREA AND 'HEARD' THE DSCNT ALONG WITH THE APCH CLRNC. ON DEBRIEFING I DISCUSSED MY MISTAKE WITH MY STUDENT AND EMPHASIZED TO BOTH OF US THE NECESSITY TO OBTAIN VERIFICATION WHEN UNSURE OF A 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.