Air carrier medium large transport departed altitude before reaching descent fix.

Attributes
ACN	102514
Time
Date	198901
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : pit
State Reference	PA
Altitude	msl bound lower : 4300 msl bound upper : 5000
Environment
Flight Conditions	IMC
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : pit
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Flight Phase	descent : approach descent other
Route In Use	approach : straight in
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 250 flight time total : 12000 flight time type : 2000
ASRS Report	102514
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : crossing restriction not met altitude deviation : excursion from assigned altitude non adherence : published procedure
Independent Detector	other controllera
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:

While executing the ILS approach to runway 28R at pit, I was flying the airplane and the first officer was monitoring the approach with the approach plate. The first officer erroneously reported that we had passed kerrs intersection (5000' mandatory crossing altitude) and so I began my descent to cross cofee intersection at 4000'. Passing through 4300' the approach monitor alerted us to the fact that we had not crossed kerrs intersection and therefore should still be at 5000'. The first officer was using montour VOR DME to identify kerrs intersection. The distance from the end of the runway to kerrs intersection is 13 NM. He assumed that the DME from montour would be 13 NM also, and failed to read the note identing kerrs intersection as actually being 11.2 DME from montour. This prompted us to begin a premature descent. The particular approach plate for the ILS 28R approach to pit is very cluttered, and the footnotes are not laid out very well. I feel that the presentation of the approach tends to add to cockpit confusion and the possibility of violations.

Original NASA ASRS Text

Title: ACR MLG DEPARTED ALT BEFORE REACHING DESCENT FIX.

Narrative: WHILE EXECUTING THE ILS APCH TO RWY 28R AT PIT, I WAS FLYING THE AIRPLANE AND THE F/O WAS MONITORING THE APCH WITH THE APCH PLATE. THE F/O ERRONEOUSLY RPTED THAT WE HAD PASSED KERRS INTXN (5000' MANDATORY XING ALT) AND SO I BEGAN MY DSCNT TO CROSS COFEE INTXN AT 4000'. PASSING THROUGH 4300' THE APCH MONITOR ALERTED US TO THE FACT THAT WE HAD NOT CROSSED KERRS INTXN AND THEREFORE SHOULD STILL BE AT 5000'. THE F/O WAS USING MONTOUR VOR DME TO IDENT KERRS INTXN. THE DISTANCE FROM THE END OF THE RWY TO KERRS INTXN IS 13 NM. HE ASSUMED THAT THE DME FROM MONTOUR WOULD BE 13 NM ALSO, AND FAILED TO READ THE NOTE IDENTING KERRS INTXN AS ACTUALLY BEING 11.2 DME FROM MONTOUR. THIS PROMPTED US TO BEGIN A PREMATURE DSCNT. THE PARTICULAR APCH PLATE FOR THE ILS 28R APCH TO PIT IS VERY CLUTTERED, AND THE FOOTNOTES ARE NOT LAID OUT VERY WELL. I FEEL THAT THE PRESENTATION OF THE APCH TENDS TO ADD TO COCKPIT CONFUSION AND THE POSSIBILITY OF VIOLATIONS.

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.