Cargo flight descends below intercept altitude on approach believing cleared to that altitude.

Attributes
ACN	212936
Time
Date	199206
Day	Thu
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : day
State Reference	OH
Altitude	msl bound lower : 2600 msl bound upper : 3000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : day
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : instrument pilot : commercial pilot : atp pilot : flight engineer
Experience	flight time last 90 days : 125 flight time total : 6700 flight time type : 1200
ASRS Report	212936
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I believe this was only a communication problem. We were almost established on the ILS 6L day at approximately 3 mi outside marker, no GS indications yet, when cleared to 2000 MSL. My first officer read back the clearance to 2000 ft MSL, which was not corrected by approach. After passing 2600 ft MSL descending, I realized that we couldn't possibly have been correctly cleared to 2000 ft MSL. The approach intercept altitude is 3000 ft! (With 'towers' approximately 2500 ft just north of the approach course). I immediately climbed to 3000 ft MSL and completed approach. We were all tired since it was about XA45 am and didn't notice the altitude should have been higher to intercept, thus we didn't question anyone. In my judgement, I believe it is more important to make sure everyone in the cockpit remembers the intercept altitude and mins!

Original NASA ASRS Text

Title: CARGO FLT DSNDS BELOW INTERCEPT ALT ON APCH BELIEVING CLRED TO THAT ALT.

Narrative: I BELIEVE THIS WAS ONLY A COM PROBLEM. WE WERE ALMOST ESTABLISHED ON THE ILS 6L DAY AT APPROX 3 MI OUTSIDE MARKER, NO GS INDICATIONS YET, WHEN CLRED TO 2000 MSL. MY FO READ BACK THE CLRNC TO 2000 FT MSL, WHICH WAS NOT CORRECTED BY APCH. AFTER PASSING 2600 FT MSL DSNDING, I REALIZED THAT WE COULDN'T POSSIBLY HAVE BEEN CORRECTLY CLRED TO 2000 FT MSL. THE APCH INTERCEPT ALT IS 3000 FT! (WITH 'TWRS' APPROX 2500 FT JUST N OF THE APCH COURSE). I IMMEDIATELY CLBED TO 3000 FT MSL AND COMPLETED APCH. WE WERE ALL TIRED SINCE IT WAS ABOUT XA45 AM AND DIDN'T NOTICE THE ALT SHOULD HAVE BEEN HIGHER TO INTERCEPT, THUS WE DIDN'T QUESTION ANYONE. IN MY JUDGEMENT, I BELIEVE IT IS MORE IMPORTANT TO MAKE SURE EVERYONE IN THE COCKPIT REMEMBERS THE INTERCEPT ALT AND MINS!

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.