Altitude excursion during approach phase.

Attributes
ACN	132825
Time
Date	198912
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dca
State Reference	DC
Altitude	msl bound lower : 4600 msl bound upper : 5000
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : dca
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	cruise other descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : flight engineer pilot : cfi pilot : atp
ASRS Report	132825
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time last 90 days : 200 flight time total : 5000 flight time type : 300
ASRS Report	132210
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : far non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
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:

We were being vectored for ILS 36 approach into dca. We were cleared down to 5000'. Because the RVR was fluctuating and marginal to make the approach with CAT I minimums, the PNF inquired about CAT ii approachs. The PNF got into a rather lengthy discussion with ATC and I diverted my attention looking for the proper approach plates. In the meantime, the PF descended to 4600'. When the altitude alert activated, the PF made an immediate power application and corrected to 5000'. This was our last leg of the day, with 6+ hours flying time and 10+ hours duty time.

Original NASA ASRS Text

Title: ALT EXCURSION DURING APCH PHASE.

Narrative: WE WERE BEING VECTORED FOR ILS 36 APCH INTO DCA. WE WERE CLRED DOWN TO 5000'. BECAUSE THE RVR WAS FLUCTUATING AND MARGINAL TO MAKE THE APCH WITH CAT I MINIMUMS, THE PNF INQUIRED ABOUT CAT II APCHS. THE PNF GOT INTO A RATHER LENGTHY DISCUSSION WITH ATC AND I DIVERTED MY ATTN LOOKING FOR THE PROPER APCH PLATES. IN THE MEANTIME, THE PF DSNDED TO 4600'. WHEN THE ALT ALERT ACTIVATED, THE PF MADE AN IMMEDIATE PWR APPLICATION AND CORRECTED TO 5000'. THIS WAS OUR LAST LEG OF THE DAY, WITH 6+ HRS FLYING TIME AND 10+ HRS DUTY TIME.

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.