Instructor with instrument student descends below assigned altitude on ILS approach.

Attributes
ACN	224336
Time
Date	199210
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : mmu
State Reference	NJ
Altitude	msl bound lower : 2400 msl bound upper : 3000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : n90
Operator	general aviation : personal
Make Model Name	Small Aircraft
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 90 flight time total : 3000 flight time type : 1000
ASRS Report	224336
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance non adherence : published procedure
Independent Detector	other controllera other flight crewa
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:

While giving instrument instruction to an instrument rated pilot on an IFR flight plan we were told by ny approach to intercept and track inbound on the initial approach bearing of the NDB 23 at mmu. The student began a rapid descent below 3000 ft to 2400 ft en route to 2000 ft (the initial altitude). By the time I caught and rectified the mistake (we were not yet cleared for the approach and should have maintained our last assigned altitude of 3000 ft) ny approach had pointed it out to us. The problem was further complicated by the student's inability to admit to an error on my verbal instructions to climb. The student momentarily argued with my instructions forcing me to physically take control of the aircraft until, or at the same time as ny approach commented. The student then became humble and relinquished control of the aircraft. The human performance factors involved were poor cockpit resource management skills on the part of the student and a slow corrective action on the part of the instructor. All was complicated by the student's lack of understanding of the controller's last instructions.

Original NASA ASRS Text

Title: INSTRUCTOR WITH INST STUDENT DSNDS BELOW ASSIGNED ALT ON ILS APCH.

Narrative: WHILE GIVING INST INSTRUCTION TO AN INST RATED PLT ON AN IFR FLT PLAN WE WERE TOLD BY NY APCH TO INTERCEPT AND TRACK INBOUND ON THE INITIAL APCH BEARING OF THE NDB 23 AT MMU. THE STUDENT BEGAN A RAPID DSCNT BELOW 3000 FT TO 2400 FT ENRTE TO 2000 FT (THE INITIAL ALT). BY THE TIME I CAUGHT AND RECTIFIED THE MISTAKE (WE WERE NOT YET CLRED FOR THE APCH AND SHOULD HAVE MAINTAINED OUR LAST ASSIGNED ALT OF 3000 FT) NY APCH HAD POINTED IT OUT TO US. THE PROBLEM WAS FURTHER COMPLICATED BY THE STUDENT'S INABILITY TO ADMIT TO AN ERROR ON MY VERBAL INSTRUCTIONS TO CLB. THE STUDENT MOMENTARILY ARGUED WITH MY INSTRUCTIONS FORCING ME TO PHYSICALLY TAKE CTL OF THE ACFT UNTIL, OR AT THE SAME TIME AS NY APCH COMMENTED. THE STUDENT THEN BECAME HUMBLE AND RELINQUISHED CTL OF THE ACFT. THE HUMAN PERFORMANCE FACTORS INVOLVED WERE POOR COCKPIT RESOURCE MGMNT SKILLS ON THE PART OF THE STUDENT AND A SLOW CORRECTIVE ACTION ON THE PART OF THE INSTRUCTOR. ALL WAS COMPLICATED BY THE STUDENT'S LACK OF UNDERSTANDING OF THE CTLR'S LAST INSTRUCTIONS.

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.