B737-700
Flight Crew Last 90 Days 49; Flight Crew Type 3000
Confusion
Aircraft Equipment Problem Critical; Inflight Event / Encounter Weather / Turbulence
Aircraft Equipment Problem Dissipated; Flight Crew Took Evasive Action
Weather; Aircraft
Flying at 40;000 FT passing over an outer band of weather from a tropical storm; the Number One Engine had a rollback to approximately 65% N1. We were IMC at -55 SAT. Turned engine ignition and engine anti-ice on and engine returned to normal operation in about one minute.
At FL400 flying over a tropical storm; we noticed ice was building on the window and windshield wiper. Temperature outside was a minus 55 degrees. The First Officer and I discussed turning the engine anti-ice on even though the temperature was -55. I looked around the HUD to look outside at ice buildup when the First Officer said we just lost the Number One Engine. I then turned the igniters to FLT and turned both engine anti-ice to ON. The Number One Engine reduced to 65% N1 and stabilized. I pushed the throttles up to get additional power and after approximately 30 seconds to one minute the Number One Engine came back up to speed. We left the anti-ice on until in the clear. No further events and we landed in our filed destination. I contacted Dispatch and they contacted Maintenance. I contacted the Chief Pilot. Maintenance said the aircraft was good to go and that when a sensor ices over it defaults to 65% N1.
A B737-700 Number One Engine rolled back to 65% N1 while flying at FL400 over a tropical storm with ice forming on the windshield at -55C. After the igniters were selected to FLT and the engine anti-ice turned ON; the engine recovered in about 30 seconds.