Flight crew descended below assigned altitude.

Attributes
ACN	430920
Time
Date	199903
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : mhtg.artcc
State Reference	FO
Altitude	msl bound lower : 19500 msl bound upper : 20000
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	430921
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument pilot : multi engine
ASRS Report	430922
Events
Anomaly	non adherence : clearance aircraft equipment problem : critical
Independent Detector	other flight crewa other flight crewb other other : 3
Resolutory Action	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:

On descent in gua we were cleared to FL200 during which time we simultaneously experienced a minor pressurization problem requiring the captain's attention. The plane unintentionally descended below FL200 momentarily but was quickly corrected back to FL200. The flight continued uneventfully. Supplemental information from acn 430921: flight engineer noticed a minor problem on the panel. While dealing with this problem, I allowed aircraft to descend to FL195. In future, will have first officer fly when dealing with even a minor problem.

Original NASA ASRS Text

Title: FLC DSNDED BELOW ASSIGNED ALT.

Narrative: ON DSCNT IN GUA WE WERE CLRED TO FL200 DURING WHICH TIME WE SIMULTANEOUSLY EXPERIENCED A MINOR PRESSURIZATION PROB REQUIRING THE CAPT'S ATTN. THE PLANE UNINTENTIONALLY DSNDED BELOW FL200 MOMENTARILY BUT WAS QUICKLY CORRECTED BACK TO FL200. THE FLT CONTINUED UNEVENTFULLY. SUPPLEMENTAL INFO FROM ACN 430921: FE NOTICED A MINOR PROB ON THE PANEL. WHILE DEALING WITH THIS PROB, I ALLOWED ACFT TO DSND TO FL195. IN FUTURE, WILL HAVE FO FLY WHEN DEALING WITH EVEN A MINOR PROB.

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.