Widebody transport aircraft has altitude deviation during step climb.

Attributes
ACN	306110
Time
Date	199505
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : lin
State Reference	CA
Altitude	msl bound lower : 25000 msl bound upper : 25300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa
Operator	common carrier : air carrier
Make Model Name	B747-100
Operating Under FAR Part	Part 121
Flight Phase	climbout : intermediate altitude
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 17500 flight time type : 1800
ASRS Report	306110
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	controller : issued new clearance
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Early morning departure, climbing straight into the sun over rising twring cumulus/cumulo nimbus. While trying to visually judge if we would clear the cumulus tops, ZOA cleared us to continue climb from FL230 to FL250. The first officer was working with the INS and missed the 'FL240 for FL250' callout. Distracted by the bright sun and cumulus clouds, I did not notice the 'altitude warning' light. The altitude deviation horn sounded at 25300 ft and I leveled immediately. About 5 seconds after leveling off at 25300 ft, ZOA cleared us to 'climb to FL290,' with no mention of the 300 ft deviation. Even though this incident apparently did not create a separation problem for ATC, the need for an aural warning when approaching (within 900 ft) of cleared altitude on the older 747's (747-100's, -200's, -238-south) is definitely brought out. The aural warning only sounds when deviating desired altitude by 300 ft and then it's too late!

Original NASA ASRS Text

Title: WDB ACFT HAS ALTDEV DURING STEP CLB.

Narrative: EARLY MORNING DEP, CLBING STRAIGHT INTO THE SUN OVER RISING TWRING CUMULUS/CUMULO NIMBUS. WHILE TRYING TO VISUALLY JUDGE IF WE WOULD CLR THE CUMULUS TOPS, ZOA CLRED US TO CONTINUE CLB FROM FL230 TO FL250. THE FO WAS WORKING WITH THE INS AND MISSED THE 'FL240 FOR FL250' CALLOUT. DISTRACTED BY THE BRIGHT SUN AND CUMULUS CLOUDS, I DID NOT NOTICE THE 'ALT WARNING' LIGHT. THE ALTDEV HORN SOUNDED AT 25300 FT AND I LEVELED IMMEDIATELY. ABOUT 5 SECONDS AFTER LEVELING OFF AT 25300 FT, ZOA CLRED US TO 'CLB TO FL290,' WITH NO MENTION OF THE 300 FT DEV. EVEN THOUGH THIS INCIDENT APPARENTLY DID NOT CREATE A SEPARATION PROB FOR ATC, THE NEED FOR AN AURAL WARNING WHEN APCHING (WITHIN 900 FT) OF CLRED ALT ON THE OLDER 747'S (747-100'S, -200'S, -238-S) IS DEFINITELY BROUGHT OUT. THE AURAL WARNING ONLY SOUNDS WHEN DEVIATING DESIRED ALT BY 300 FT AND THEN IT'S TOO LATE!

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.