After takeoff B737-800 passengers reported a spoiler up and the generator off light alerted so an em...

Narrative:

Took off and assigned 180 heading immediately after switching to departure. Noticed the steady rumble at the controls also immediately after clean up. Commented to the captain that something was wrong when we got a master caution and generator off light on left engine. Cabin chimed about that time to say passengers thought spoilers were up on left side. I took the radios and continued to fly and informed ATC that we were declaring an emergency and requested level off at next altitude coming up which was 11;000. I started the APU and asked for vectors back around to land at the departure airport. The descent and configuring for landing were still controllable though the rumble continued. The engine; other than the generator; operated normally. The landing was normal at flaps 30 with auto brakes 2. Weather was cavu and wind 260/4. The cowling departed the aircraft on landing; and I assume when I went into reverse. It was retrieved on the runway. No leaks or other damage was noted by fire trucks so we taxied back to the gate. Lost cowling to left engine which also cut generator for that engine.

Original NASA ASRS Text

Title: After takeoff B737-800 passengers reported a spoiler up and the Generator OFF light alerted so an emergency was declared and the flight returned to the departure airport where a left engine access panel was discovered missing.

Narrative: Took off and assigned 180 heading immediately after switching to departure. Noticed the steady rumble at the controls also immediately after clean up. Commented to the Captain that something was wrong when we got a Master Caution and Generator OFF Light on left engine. Cabin chimed about that time to say passengers thought spoilers were up on left side. I took the radios and continued to fly and informed ATC that we were declaring an emergency and requested level off at next altitude coming up which was 11;000. I started the APU and asked for vectors back around to land at the departure airport. The descent and configuring for landing were still controllable though the rumble continued. The engine; other than the generator; operated normally. The landing was normal at flaps 30 with auto brakes 2. Weather was CAVU and wind 260/4. The cowling departed the aircraft on landing; and I assume when I went into reverse. It was retrieved on the runway. No leaks or other damage was noted by fire trucks so we taxied back to the gate. Lost cowling to left engine which also cut generator for that engine.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1018838
Time
Date	201206
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Flight Phase	Climb Initial Climb
Flight Plan	IFR
Component
Aircraft Component	Generator Drive
Person 1
Function	First Officer Pilot Flying
Person 2
Function	Pilot Not Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Critical

After takeoff B737-800 passengers reported a spoiler up and the generator off light alerted so an emergency was declared and the flight returned to the departure airport where a left engine access panel was discovered missing.