A cruising L188 has difficulty in maintaining its altitude when near thunderstorm activity.

Attributes
ACN	418310
Time
Date	199810
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : pln
State Reference	MI
Altitude	msl bound lower : 17500 msl bound upper : 18300
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zmp
Operator	common carrier : air carrier
Make Model Name	Electra L-188
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 120 flight time total : 20000 flight time type : 15000
ASRS Report	418310
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial pilot : atp
Experience	flight time last 90 days : 230 flight time total : 4200
ASRS Report	418313
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter other non adherence : clearance other anomaly
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course flight crew : regained aircraft control
Consequence	Other
Supplementary
Primary Problem	Weather
Air Traffic Incident	Pilot Deviation

Narrative:

Turbulent air: aircraft pitched up to FL183 then descended to approximately 17500 ft. Climbed back to assigned (FL180). Total time of occurrence approximately 30 seconds or less.

Original NASA ASRS Text

Title: A CRUISING L188 HAS DIFFICULTY IN MAINTAINING ITS ALT WHEN NEAR TSTM ACTIVITY.

Narrative: TURBULENT AIR: ACFT PITCHED UP TO FL183 THEN DSNDED TO APPROX 17500 FT. CLBED BACK TO ASSIGNED (FL180). TOTAL TIME OF OCCURRENCE APPROX 30 SECONDS OR LESS.

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.