Descended below assigned altitude. Airborne conflict.

Attributes
ACN	88835
Time
Date	198806
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ict
State Reference	KS
Altitude	msl bound lower : 3000 msl bound upper : 3500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ict tracon : pvd
Operator	general aviation : personal
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Flight Phase	descent : approach
Flight Plan	None
Aircraft 2
Make Model Name	Small Aircraft, High Wing, 1 Eng, Retractable Gear
Flight Phase	cruise other
Person 1
Affiliation	Other
Function	instruction : trainee
Qualification	pilot : private
Experience	flight time last 90 days : 90 flight time total : 192 flight time type : 25
ASRS Report	88835
Person 2
Function	instruction : instructor
Qualification	pilot : cfi
Events
Anomaly	altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : clearance
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Miss Distance	horizontal : 0 vertical : 200
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

While conducting approach to runway 19R ATC said to maintain 3500' and to report established on the approach. After being established on the approach, I reported 'established on ILS 19R approach.' ATC approach acknowledged. I then began a descent according to the published approach procedure and leveled off at 3000'. Prior to being established, traffic was called out at our 7 O'clock position and overtaking us. Other traffic reported visual contact with us. Traffic passed below us at about 200', below our altitude from 7 to 2 O'clock positions. We first saw aircraft when it reached our 2 O'clock position. No maneuvering was required by either aircraft. Upon leveling off at 3000', approach called us and informed us that they had not given us permission to descend below 3500'. I feel this incident occurred because of confusion between being established on the approach and being cleared for the approach. It would have helped if ATC had repeated to maintain 3500' until cleared for the approach, or until further notice. At the time, I reported established on ILS 19R approach. Callback conversation with reporter revealed the following: indicates pilot in training for instrument rating, under hood, never saw the other aircraft. No evasive action taken. Learned need to listen carefully to controller phraseology.

Original NASA ASRS Text

Title: DESCENDED BELOW ASSIGNED ALT. AIRBORNE CONFLICT.

Narrative: WHILE CONDUCTING APCH TO RWY 19R ATC SAID TO MAINTAIN 3500' AND TO RPT ESTABLISHED ON THE APCH. AFTER BEING ESTABLISHED ON THE APCH, I RPTED 'ESTABLISHED ON ILS 19R APCH.' ATC APCH ACKNOWLEDGED. I THEN BEGAN A DSCNT ACCORDING TO THE PUBLISHED APCH PROC AND LEVELED OFF AT 3000'. PRIOR TO BEING ESTABLISHED, TFC WAS CALLED OUT AT OUR 7 O'CLOCK POS AND OVERTAKING US. OTHER TFC RPTED VISUAL CONTACT WITH US. TFC PASSED BELOW US AT ABOUT 200', BELOW OUR ALT FROM 7 TO 2 O'CLOCK POSITIONS. WE FIRST SAW ACFT WHEN IT REACHED OUR 2 O'CLOCK POS. NO MANEUVERING WAS REQUIRED BY EITHER ACFT. UPON LEVELING OFF AT 3000', APCH CALLED US AND INFORMED US THAT THEY HAD NOT GIVEN US PERMISSION TO DSND BELOW 3500'. I FEEL THIS INCIDENT OCCURRED BECAUSE OF CONFUSION BTWN BEING ESTABLISHED ON THE APCH AND BEING CLRED FOR THE APCH. IT WOULD HAVE HELPED IF ATC HAD REPEATED TO MAINTAIN 3500' UNTIL CLRED FOR THE APCH, OR UNTIL FURTHER NOTICE. AT THE TIME, I RPTED ESTABLISHED ON ILS 19R APCH. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: INDICATES PLT IN TRNING FOR INSTRUMENT RATING, UNDER HOOD, NEVER SAW THE OTHER ACFT. NO EVASIVE ACTION TAKEN. LEARNED NEED TO LISTEN CAREFULLY TO CTLR PHRASEOLOGY.

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.