Altitude deviation during a return land event.

Attributes
ACN	206997
Time
Date	199204
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : pom airport : poc
State Reference	CA
Altitude	msl bound lower : 2700 msl bound upper : 3000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ont
Operator	general aviation : instructional
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	instruction : instructor oversight : pic
Qualification	pilot : cfi
Experience	flight time last 90 days : 40 flight time total : 3600
ASRS Report	206997
Person 2
Affiliation	Other
Function	flight crew : single pilot instruction : trainee
Qualification	pilot : private
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera other flight crewa
Resolutory Action	none taken : anomaly accepted
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Shortly after takeoff on an instrument training flight intended to practice approachs at ral, cno, and poc, a strong odor of burning oil was noticed causing great concern to the student a moment later, while climbing through 3800 ft for the assigned altitude of 5000 ft, the engine became quite rough. Carburetor heat, mixture and magnetos were checked without helpful results. We requested a return to brackett notifying approach control of our problem but not declaring an emergency, as all engine gauges were normal and the slight power loss and shaking were not too alarming considering our proximity to brackett. We were offered either the ILS approach or vectors, and accepted a vector return. We were descended to 3000 ft and vectored along the normal VOR approach. About 1/2 mi inside of goldie (FAF for VOR approach), I allowed the aircraft to descend about 300 ft below the assigned altitude, probably due to my extreme familiarity with the VOR approach and recognizing the terrain which would have permitted 1800 ft at that position. Approach notified me of the lower than assigned altitude, and as we had broken out and had the airport insight, cleared me to tower.

Original NASA ASRS Text

Title: ALTDEV DURING A RETURN LAND EVENT.

Narrative: SHORTLY AFTER TKOF ON AN INST TRAINING FLT INTENDED TO PRACTICE APCHS AT RAL, CNO, AND POC, A STRONG ODOR OF BURNING OIL WAS NOTICED CAUSING GREAT CONCERN TO THE STUDENT A MOMENT LATER, WHILE CLBING THROUGH 3800 FT FOR THE ASSIGNED ALT OF 5000 FT, THE ENG BECAME QUITE ROUGH. CARB HEAT, MIXTURE AND MAGNETOS WERE CHKED WITHOUT HELPFUL RESULTS. WE REQUESTED A RETURN TO BRACKETT NOTIFYING APCH CTL OF OUR PROBLEM BUT NOT DECLARING AN EMER, AS ALL ENG GAUGES WERE NORMAL AND THE SLIGHT PWR LOSS AND SHAKING WERE NOT TOO ALARMING CONSIDERING OUR PROX TO BRACKETT. WE WERE OFFERED EITHER THE ILS APCH OR VECTORS, AND ACCEPTED A VECTOR RETURN. WE WERE DSNDED TO 3000 FT AND VECTORED ALONG THE NORMAL VOR APCH. ABOUT 1/2 MI INSIDE OF GOLDIE (FAF FOR VOR APCH), I ALLOWED THE ACFT TO DSND ABOUT 300 FT BELOW THE ASSIGNED ALT, PROBABLY DUE TO MY EXTREME FAMILIARITY WITH THE VOR APCH AND RECOGNIZING THE TERRAIN WHICH WOULD HAVE PERMITTED 1800 FT AT THAT POS. APCH NOTIFIED ME OF THE LOWER THAN ASSIGNED ALT, AND AS WE HAD BROKEN OUT AND HAD THE ARPT INSIGHT, CLRED ME TO TWR.

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.