Altitude excursion occurs as air carrier pilot of widebody transport descends prematurely on localiz...

Attributes
ACN	131488
Time
Date	198912
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : msy
State Reference	LA
Altitude	msl bound lower : 1100 msl bound upper : 2100
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	tracon : msy tower : msy
Operator	common carrier : air carrier
Make Model Name	Widebody, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent : approach descent other
Route In Use	arrival other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 180 flight time total : 15000 flight time type : 3000
ASRS Report	131488
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot conflict : ground less severe non adherence : published procedure non adherence : clearance non adherence : far
Independent Detector	atc equipment other atc equipment : unspecified other controllera
Resolutory Action	controller : issued new clearance flight crew : became reoriented other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

I was flying from dfw to new orleans in 12/89. The ceiling was reported to be 1300' with good visibility. Wind was, I believe, 360 degrees at 9 KTS. I was expecting an ILS to runway 1. The new orleans ATIS reported landing to the east. We were cleared for a localizer approach to runway 10. There had been NOTAMS of a displaced threshold, OM problems, and of course, no G/south on a localizer approach. We were unable to pick up any DME on the localizer approach. We were unable to pick up any DME on the localizer frequency. Because of the cloud coverage at the airport, I was attempting to plan my descent so there would be no need for any rapid dscnts for landing. Kinte was tuned on the ADF, but I do not remember if it was pointing correctly. Since I could not pick up DME on the localizer frequency, I was substituting omega DME because it was our only reference as to distance from new orleans and the outer localizer kinte. When our omega DME read 8 mi, I started final descent from 2100'. At 1100' (still in clouds) the tower operator told us to check our altitude and that we should be at 2100' over kinte. I immediately leveled off and we all hastened to verify our position. At this point the localizer DME briefly read 8 mi and then went blank again. We broke out of the clouds and were able to establish our position visually. We were then able to proceed visually to the airport for a normal landing. After we had broken out of the clouds, I informed the tower operator that the localizer DME was intermittent and unreliable. She said she had had a previous similar report. First of all, I would like to thank new orleans tower operator for her alertness. Her quick action allowed us to correct the problem and proceed safely. I do, however, question the use of runway 10 under marginal ceiling conditions when it had no G/south and a reported DME problem. And if runway 10 is to be used, the reported DME problem should be reported to the pilot before starting the approach rather than during the approach.

Original NASA ASRS Text

Title: ALT EXCURSION OCCURS AS ACR PLT OF WDB DESCENDS PREMATURELY ON LOCALIZER APCH. CLAIMS INOPERATIVE DME WAS PROBLEM. CITES AS CONTRIBUTORY THE DESIRE TO MAKE PROPER STABILIZED APCH AND THE CLOUD COVER OBSCURING THE ARPT.

Narrative: I WAS FLYING FROM DFW TO NEW ORLEANS IN 12/89. THE CEILING WAS RPTED TO BE 1300' WITH GOOD VISIBILITY. WIND WAS, I BELIEVE, 360 DEGS AT 9 KTS. I WAS EXPECTING AN ILS TO RWY 1. THE NEW ORLEANS ATIS RPTED LNDG TO THE E. WE WERE CLRED FOR A LOC APCH TO RWY 10. THERE HAD BEEN NOTAMS OF A DISPLACED THRESHOLD, OM PROBS, AND OF COURSE, NO G/S ON A LOC APCH. WE WERE UNABLE TO PICK UP ANY DME ON THE LOC APCH. WE WERE UNABLE TO PICK UP ANY DME ON THE LOC FREQ. BECAUSE OF THE CLOUD COVERAGE AT THE ARPT, I WAS ATTEMPTING TO PLAN MY DSCNT SO THERE WOULD BE NO NEED FOR ANY RAPID DSCNTS FOR LNDG. KINTE WAS TUNED ON THE ADF, BUT I DO NOT REMEMBER IF IT WAS POINTING CORRECTLY. SINCE I COULD NOT PICK UP DME ON THE LOC FREQ, I WAS SUBSTITUTING OMEGA DME BECAUSE IT WAS OUR ONLY REFERENCE AS TO DISTANCE FROM NEW ORLEANS AND THE OUTER LOC KINTE. WHEN OUR OMEGA DME READ 8 MI, I STARTED FINAL DSCNT FROM 2100'. AT 1100' (STILL IN CLOUDS) THE TWR OPERATOR TOLD US TO CHK OUR ALT AND THAT WE SHOULD BE AT 2100' OVER KINTE. I IMMEDIATELY LEVELED OFF AND WE ALL HASTENED TO VERIFY OUR POS. AT THIS POINT THE LOC DME BRIEFLY READ 8 MI AND THEN WENT BLANK AGAIN. WE BROKE OUT OF THE CLOUDS AND WERE ABLE TO ESTABLISH OUR POS VISUALLY. WE WERE THEN ABLE TO PROCEED VISUALLY TO THE ARPT FOR A NORMAL LNDG. AFTER WE HAD BROKEN OUT OF THE CLOUDS, I INFORMED THE TWR OPERATOR THAT THE LOC DME WAS INTERMITTENT AND UNRELIABLE. SHE SAID SHE HAD HAD A PREVIOUS SIMILAR RPT. FIRST OF ALL, I WOULD LIKE TO THANK NEW ORLEANS TWR OPERATOR FOR HER ALERTNESS. HER QUICK ACTION ALLOWED US TO CORRECT THE PROBLEM AND PROCEED SAFELY. I DO, HOWEVER, QUESTION THE USE OF RWY 10 UNDER MARGINAL CEILING CONDITIONS WHEN IT HAD NO G/S AND A RPTED DME PROB. AND IF RWY 10 IS TO BE USED, THE RPTED DME PROB SHOULD BE RPTED TO THE PLT BEFORE STARTING THE APCH RATHER THAN DURING THE APCH.

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.

Altitude excursion occurs as air carrier pilot of widebody transport descends prematurely on localizer approach. Claims inoperative DME was problem. Cites as contributory the desire to make proper stabilized approach and the cloud cover obscuring the airport.