Crew failed to maintain assigned altitude.

Attributes
ACN	429419
Time
Date	199903
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : iah.airport
State Reference	TX
Altitude	msl bound lower : 4000 msl bound upper : 4300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : i90.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tracon : i90.tracon
Route In Use	approach : instrument precision
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 15 flight time total : 10000 flight time type : 450
ASRS Report	429419
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : flight engineer pilot : multi engine pilot : atp
Experience	flight time last 90 days : 150 flight time total : 3000 flight time type : 400
ASRS Report	429604
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera other flight crewa other flight crewb
Resolutory Action	controller : issued advisory flight crew : returned to original clearance
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Aircraft being vectored to runway 26 ILS at 4000 ft MSL. After a heading to intercept final was assigned, autoplt was disengaged in anticipation of hand flying the final portion of the approach. Subsequently, the runway assignment was changed to ILS runway 27, a new heading assigned and traffic was called out by the controller (several calls). While maneuvering and looking for traffic, aircraft climbed 300 ft. Contributing factors: hand flying while maneuvering, looking for aircraft and trying to comply with a revised clearance (runway assignment). Deviation discovered simultaneously by pilots and controller. Aircraft flown back to altitude and autoplt re-engaged. Human performance: not utilizing autoplt in a timely manner when workload increased significantly. Distraction from flying aircraft while looking for traffic.

Original NASA ASRS Text

Title: CREW FAILED TO MAINTAIN ASSIGNED ALT.

Narrative: ACFT BEING VECTORED TO RWY 26 ILS AT 4000 FT MSL. AFTER A HDG TO INTERCEPT FINAL WAS ASSIGNED, AUTOPLT WAS DISENGAGED IN ANTICIPATION OF HAND FLYING THE FINAL PORTION OF THE APCH. SUBSEQUENTLY, THE RWY ASSIGNMENT WAS CHANGED TO ILS RWY 27, A NEW HDG ASSIGNED AND TFC WAS CALLED OUT BY THE CTLR (SEVERAL CALLS). WHILE MANEUVERING AND LOOKING FOR TFC, ACFT CLBED 300 FT. CONTRIBUTING FACTORS: HAND FLYING WHILE MANEUVERING, LOOKING FOR ACFT AND TRYING TO COMPLY WITH A REVISED CLRNC (RWY ASSIGNMENT). DEV DISCOVERED SIMULTANEOUSLY BY PLTS AND CTLR. ACFT FLOWN BACK TO ALT AND AUTOPLT RE-ENGAGED. HUMAN PERFORMANCE: NOT UTILIZING AUTOPLT IN A TIMELY MANNER WHEN WORKLOAD INCREASED SIGNIFICANTLY. DISTR FROM FLYING ACFT WHILE LOOKING FOR TFC.

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.