First officer forgot to remove one of the landing gear pins resulting in return land.

Attributes
ACN	311068
Time
Date	199507
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : smf
State Reference	CA
Altitude	agl bound lower : 50 agl bound upper : 150
Environment
Flight Conditions	VMC
Light	Dawn
Aircraft 1
Controlling Facilities	tower : smf
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	climbout : initial climbout : takeoff other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 10000 flight time type : 3000
ASRS Report	311068
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : less severe non adherence : published procedure
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	Pilot Deviation

Narrative:

I conducted a normal preflight for flight service from smf to lax at XA45 local time jul/xx/95. I was not rushed for any reason or distracted. I was alert and ready for the day's sequence. For some reason, I inadvertently left the right main gear pin in place and proceeded on my preflight. With my flashlight and 2 gear pins in 1 hand, I did not notice the third missing. While reading the before start checklist the captain felt in the back pocket for gear pins, found them, but did not count them. Therefore, our third chance for finding this error past. We departed on time for lax. However, when we raised the gear the right main stayed down. We discovered very shortly thereafter what had happened and requested to return to the airport. We ran all checklists and landed uneventfully. The aircraft was inspected by maintenance, a new release was issued, and the aircraft was returned to service.

Original NASA ASRS Text

Title: FO FORGOT TO REMOVE ONE OF THE LNDG GEAR PINS RESULTING IN RETURN LAND.

Narrative: I CONDUCTED A NORMAL PREFLT FOR FLT SVC FROM SMF TO LAX AT XA45 LCL TIME JUL/XX/95. I WAS NOT RUSHED FOR ANY REASON OR DISTRACTED. I WAS ALERT AND READY FOR THE DAY'S SEQUENCE. FOR SOME REASON, I INADVERTENTLY LEFT THE R MAIN GEAR PIN IN PLACE AND PROCEEDED ON MY PREFLT. WITH MY FLASHLIGHT AND 2 GEAR PINS IN 1 HAND, I DID NOT NOTICE THE THIRD MISSING. WHILE READING THE BEFORE START CHKLIST THE CAPT FELT IN THE BACK POCKET FOR GEAR PINS, FOUND THEM, BUT DID NOT COUNT THEM. THEREFORE, OUR THIRD CHANCE FOR FINDING THIS ERROR PAST. WE DEPARTED ON TIME FOR LAX. HOWEVER, WHEN WE RAISED THE GEAR THE R MAIN STAYED DOWN. WE DISCOVERED VERY SHORTLY THEREAFTER WHAT HAD HAPPENED AND REQUESTED TO RETURN TO THE ARPT. WE RAN ALL CHKLISTS AND LANDED UNEVENTFULLY. THE ACFT WAS INSPECTED BY MAINT, A NEW RELEASE WAS ISSUED, AND THE ACFT WAS RETURNED TO SVC.

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.