Air carrier turbojet descends below approach procedure altitude in san airspace.

Attributes
ACN	421124
Time
Date	199811
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : san
State Reference	CA
Altitude	msl bound lower : 2000 msl bound upper : 2000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Route In Use	arrival : profile descent arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 3500
ASRS Report	421124
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
Events
Anomaly	altitude deviation : crossing restriction not met non adherence : published procedure other spatial deviation
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Consequence	Other
Supplementary
Air Traffic Incident	Pilot Deviation

Narrative:

We were cleared the localizer runway 27 approach into san. DME was not reliable and was on the ATIS but we missed it. DME appeared good -- steady mileage -- no flags. We descended below specified altitudes on the approach, mainly 2000 ft to reebo. Approach got a low altitude alert on us and asked us if we were in visual conditions. We were and approach cleared us the visual approach to runway 27. An uneventful landing was made. Contributing factors: ATIS at a lot of airports has so much extra airport information that when using ACARS, you tend to 'skim' through it. Flying with an experienced and proficient crew member, you fail to xchk as diligently as usual. ATC should have mentioned the DME 'unreliable' when giving the approach clearance.

Original NASA ASRS Text

Title: ACR TURBOJET DSNDS BELOW APCH PROC ALT IN SAN AIRSPACE.

Narrative: WE WERE CLRED THE LOC RWY 27 APCH INTO SAN. DME WAS NOT RELIABLE AND WAS ON THE ATIS BUT WE MISSED IT. DME APPEARED GOOD -- STEADY MILEAGE -- NO FLAGS. WE DSNDED BELOW SPECIFIED ALTS ON THE APCH, MAINLY 2000 FT TO REEBO. APCH GOT A LOW ALT ALERT ON US AND ASKED US IF WE WERE IN VISUAL CONDITIONS. WE WERE AND APCH CLRED US THE VISUAL APCH TO RWY 27. AN UNEVENTFUL LNDG WAS MADE. CONTRIBUTING FACTORS: ATIS AT A LOT OF ARPTS HAS SO MUCH EXTRA ARPT INFO THAT WHEN USING ACARS, YOU TEND TO 'SKIM' THROUGH IT. FLYING WITH AN EXPERIENCED AND PROFICIENT CREW MEMBER, YOU FAIL TO XCHK AS DILIGENTLY AS USUAL. ATC SHOULD HAVE MENTIONED THE DME 'UNRELIABLE' WHEN GIVING THE APCH CLRNC.

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.