Date: 201809
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Light: Daylight
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Takeoff / Launch
Aircraft component: Nose Gear
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Returned To Departure Airport
Contributing factors: Procedure; Human Factors
Primary problem: Ambiguous

Narrative: I was the First Officer. The Captain and I arrived at the aircraft approximately 40 minutes prior to departure. I was notified by the Ops Agent that our flight was on a hold due to a security event at our destination; and she would advise us when she knew more. I went down to the aircraft and began getting it ready for our flight. I conducted the walk around as I usually do; inspecting the aircraft and noting anything that I see that may be out of the ordinary. On my walk around; I noticed the nose wheel assembly was brand new. I looked at it for a longer than normal time because of how clean it was. After my walk around I went into the cockpit and advised the Captain that it appeared the nose wheel assembly was brand new. He said he noticed it in the logbook also. Nothing more about it was said. Approximately three hours later our hold was lifted. We boarded; taxied out normally; and departed. The Captain was the Pilot Flying. He called for landing gear up and I selected the landing gear handle up. I normally watch the lights on the gear indicator panel go out when I do this. In the left turn out (assigned by Tower); I noticed the NOSE GEAR light did not extinguish. I told the Captain that it was on; he said 'OK' and climbed out normally. We talked to Departure and continued to climb normally. The Captain called for the QRH for the gear light and I promptly retrieved and began running the checklist. We determined that continuing to our destination was not an option with the nose gear down and began talking about our options. He had me get landing numbers to see if we could get back in which we could. He then had me message Dispatch informing them of our issue. We leveled off at 23;000 feet. During that time; I was off the radio (messaging Dispatch and calling Station Ops) [and] the Captain informed ATC that we were having a landing gear issue and that we might be returning. They said whatever we needed; let them know. The Captain advised the passengers of the issue; and assured them it was not an emergency and a normal landing back would be made. Once level and slowed to about 220 knots; the Captain asked that I lower the landing gear. This was to make sure that we would in fact get three green gear indications and that a further problem hadn't come up. We did get three green indications. I was then asked to raise the landing gear which I did. The red NOSE WHEEL light illuminated once again. We inputted the landing data; got the ATIS; set up the flight deck for an approach; and the Captain briefed it all. We then accomplished the Descent Checklist and turned back toward the airport. The subsequent 100 miles or so were uneventful. We landed normally. No emergency was declared; and equipment was not requested. Once we arrived at the gate; we were met by Maintenance Personnel. I was asked to complete my post flight duties and then to call Scheduling to advise them of our return and to get them working on what was going to happen with us as we were nearing our duty day limits. I completed my post flight tasks; and the Captain went downstairs to talk to Maintenance and look at the nose wheel. He returned fairly quickly; and told me that somehow; a BOLT was inserted into the landing gear pin hole; and it was sitting flush with the assembly and was incredibly hard to see. We noted MANY times how we had all three landing gear pins in the cockpit with us; during the preflight; during the Before Start Originating Checklist; level at 23;000 feet; when discussing the issue; and once he arrived back into the cockpit. We packed up our stuff as Maintenance said they were taking the aircraft. On our way out; I noticed a Mechanic had the bolt in his hand. I asked to see it. I asked; 'What kind of bolt is this?' He stated; 'I have no idea. It is not a bolt for the 737. Apparently the guys were having a sensor issue while replacing the nose wheel assembly and did not want to come to the cockpit to get the pins; so they put thisin there instead. I was FLOORED. A non-standard; non-Boeing; non 737 bolt was installed in the pin hole. He stated; 'This is on us; I'm so sorry. It clearly will not happen again. Now I have to find out where this came from.' He left up the jetway with the Captain and I followed shortly behind.I've been at Company for about 14 months; and in training (which is still very fresh); I'm trained to look for gear pins in the nose wheel area. These pins protrude out a good distance from the assembly; are textured; have glow in the dark rings; and have a massive red flag attached to them. When I look in the general area; THAT'S what I'm looking for. I admittedly did not see this bolt. It was completely hidden from view because of its small size; lack of texturing; and lack of a flag. Maintenance needs to adhere to company policy when inserting gear pins. The pins from the flight deck need to be used. A logbook entry should be made showing the insertion of the pins; and a corrective action should be made when pins are removed. Non-standard; non-Boeing; non 737 bolts should not be used by Maintenance when doing landing gear work.


Second narrative: We arrived at approximately 40 minutes prior to departure. We were advised by the Ops Agent that the flight would be pushing late because of an airport security issue. The First Officer was the first to enter the aircraft and began his preflight duties; beginning with a logbook check. I then reviewed the logbook and we were both aware that the aircraft underwent maintenance on the nose gear assembly. I removed the landing gear pins and counted them to make sure all three pins were onboard. When the First Officer returned; he commented that it appeared the entire nose landing gear assembly was replaced and I replied that the logbook was signed off for the work accomplished. The preflight; engine start; and taxi were uneventful. Shortly after takeoff; while retracting the landing gear; the red nose gear light remained illuminated; indicating a disagreement between the nose landing gear and the position of the landing gear handle.I was the Pilot Flying and the First Officer was the Pilot Monitoring. I continued flying; cleaned up the aircraft; and then called for the QRH Checklist for landing gear disagree. We remained at 240 KIAS and let Departure Control know that we were working a problem with our landing gear and would like to continue flying at 240 KIAS (we were assigned 250 KIAS by ATC per the SID). We continued the departure and climb to FL230 while we accomplished the QRH Checklist. We accomplished the QRH steps to a four block notation indicating the end of the checklist. Since flight with an extended nose gear would invalidate our fuel consumption data; we decided to return to the airport. The QRH Checklist ended where we began; with the landing gear in the up position and the nose gear in disagreement.We had to decide our next course of action; and elected to slow the aircraft down below 230 KIAS and extend the landing gear to determine if we would get a safe landing gear indication; which we did. We decided to return to ZZZ and contacted Dispatch; notifying them of our situation and plan. We accomplished the items in the diversion information section of the normal checklist; and ensured we had safe landing data. We notified Air Traffic Control (ATC) of our intentions to return; and I made an announcement to our passengers indicating that we were unable to continue the flight because the nose landing gear would not fully retract. I also stated that the gear would extend normally and we were going to make a normal approach and landing back and taxi back to the gate where we would have more information for their flight. I reiterated that we were not in an emergency and that we would be making a normal approach and landing. After my PA; I contacted the flight attendants and asked if my PA was loud and clear enough to be heard by the passengers; and the A Flight Attendant confirmed that it was. ATC also asked if we were declaring an emergency; and since we had a safe landing gear indication; we chose not to declare an emergency; but to continue normally. The approach and landing were uneventful. The aircraft was not overweight; nor was brake cooling indicated by our landing data for a flaps 40 approach. We contacted Station Ops prior to landing for a gate assignment. After landing we parked; shut down; deplaned the passengers; and met Maintenance Personnel. Upon inspection; Maintenance found a bolt inserted into the hole reserved for the landing gear pin and a nut fastened to the end of the bolt. Landing gear pins are highly visible and easily discernible; with or without; a red streamer and a landing gear pin was not inserted in the nose landing gear. The bolt; however; was inconspicuous; and even appeared to be a part of the nose gear assembly. In fact; the head of the bolt appeared as the hole used for the landing gear pin insertion point. The First Officer looked for a landing gear pin; and did not find one inserted in the nose landing gear. I also; being aware that maintenance was conducted earlier; removed the landing gear pins from the stowage compartment and counted them to ensure all three were aboard the aircraft during my preflight. After deplaning the passengers; I contacted Dispatch; who set up a conference call with the Superintendent of Dispatch and the Chief Pilot on Call; and I explained the details of the event. I was transferred to the Maintenance Controller and I explained the event to him. I wrote up the discrepancy in the logbook and also indicated neither a heavy weight landing; nor high energy braking; occurred. I do not believe the average pilot would catch the non-standard use of a nut and bolt in lieu of a landing gear pin. The First Officer I was flying with; in my opinion; is better than average and the bolt was not noticed. The return back was uneventful; and our training allowed us to safely assess and balance the situation and return without incident. Learning about the bolt inserted into the nose gear instead of the landing gear pin; however; was something that I found upsetting and I hope that this narrative helps to mitigate something like this in the future. In this case; Maintenance needs to be made aware of what happened and remind the Maintenance Technicians not to use anything but a landing gear pin to pin the landing gear during maintenance. Pilots are trained to look for landing gear pins and streamers; not foreign objects placed where landing gear pins belong.


Synopsis: B-737 flight crew and maintenance technicians reported that the aircraft nose gear would not retract after takeoff. Later a shipping bolt was discovered in the landing gear safety pin hole on the down-lock mechanism of the recently replaced nose gear assembly.