B737-700
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 439; Flight Crew Type 9500
Situational Awareness
Aircraft Equipment Problem Less Severe
Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport
Aircraft
Tire tread separation left nose gear at rotate speed. Excellent assistance provided by Tower; approach and ground control and also Crash Fire and Rescue throughout the flight.
We took the aircraft from the incoming Crew. They briefed us that the aircraft had shimmied a bit. Hearing this on an aircraft exchange is not terribly unusual. On the preflight walk around; I looked at the nose gear but did not notice anything out of the ordinary. On taxi out; the aircraft taxied smoothly. On takeoff roll; no shimmy was noticed until immediately prior to rotation. At that point; a shimmy developed. For the very first split second; it did not seem out of the ordinary but it very quickly progressed into a large shimmy with a significant amount of accompanying aircraft vibration as we rotated.As the nose was rotating off the ground; I saw black debris fly up from beneath the aircraft; strike my wind screen; and fly over the top of the aircraft. I was very confident we had lost a landing gear tire. I suspected a nose gear tire. However; I also thought it could be a main gear tire. I also thought there was a small possibility that we could have struck a large bird just as we were about to rotate.As we became airborne; it was fairly obvious to the Captain and I that the landing gear might be damaged and that raising the gear could exacerbate that damage. We left the gear extended. Our immediate concern was that we may have ingested debris into one or both engines. Both of us immediately examined the engine instruments to evaluate their condition. Everything looked good as we continued to climb. We also left the flaps extended at 1 in case the flap tracks had been damaged.After we had climbed to 3000 ft; our next concern was to determine if the debris had pierced the wings at all. The Captain asked the FA's (Flight Attendants) to examine the wings. They reported no visible damage. We monitored fuel balance throughout the flight in case the debris had caused a fuel leak. No fuel leak was ever noticed.Both the Captain and I discussed where we would be going. Since the weather was VMC; we had elected to leave the gear down; we both decided that returning; after burning down gas was our plan.We pulled out the QRH and opened it to the Table of Contents for Landing Gear. We decided that the Partial or All Gear Up Landing checklist was the most appropriate checklist to run for our situation. We began to run that checklist while simultaneously coordinating with Tower for a fly-by to allow them an opportunity to visually assess the damage to the landing gear. On that pass; they reported that our left nose gear tire looked smaller than our right nose gear tire.Following that pass; I became concerned in my mind that the Partial or All Gear Up Landing checklist was not really covering all the bases for our situation. By sheer coincidence; I had just been studying the Non-Normal Section of the AOM (Aircraft Operations Manual) that morning and realized that there could be information there that was more applicable to our situation. I opened up the AOM on the EFB and used the Table of Contents feature to open the Landing Gear Section. In that section; there are two items that directly applied to our situation: Tire Failure During or After Takeoff and Landing on a Flat Tire. We read through both of those checklists (several times over the course of the flight). These sections were very helpful.The Captain and I discussed the possibility that the flaps might be damaged and weighed the possibility of landing with our current flap setting (1). We decided it was worth the risk to attempt to achieve a higher flap setting in order to obtain a slower approach speed on our approach with a nose gear issue. We discussed what we would do if an asymmetry developed as we extended the flaps. We disconnected the autopilot and extended the flaps to 2; and then to 5. We then read through the AOM explanation for Damage Assessment and Aircraft Handling Evaluation. We decided we would perform those steps after we climbed to a higher altitude.We performed two more low approaches for Tower to examine our landing gear. Wewere then sent to holding. In holding; we climbed from 3000 ft to 6000 ft. While in holding; we performed the Damage Assessment and Aircraft Handing Evaluation and achieved a flap setting of 40 with no control difficulties. The Captain also coordinated with the FA's for a ground evacuation in case one should become necessary on landing if the nose gear collapsed.As we approached 13;000 pounds of fuel remaining; we requested vectors back for one final low approach at a flaps 40 setting (a slower airspeed) to give ourselves a final; better chance for Tower to visually confirm our malfunction. By this time; the Fire Department was also able to visually examine our aircraft. Both reported that the left nose gear tire appeared to be damaged and the right nose gear tire appeared normal.We then made a flaps 40 approach. On touchdown; the Captain slowly lowered the nose gear to the runway. As it touched down; it made more noise and shudder than a typical landing. However; no control difficulty was encountered and the aircraft remained on center line. We stopped straight ahead. The Fire Department was immediately on the scene. They confirmed the left nose gear tire was damaged; the right nose gear tire was intact; and there was no smoke or fire of any sort. The Captain and I decided that the best course of action was to taxi into the gate very slowly while being followed by the Fire Department vehicles in case a fire or other emergency developed. We got to the gate and deplaned the Passengers normally via the jet bridge.Reports of nose gear shimmy are very common. Perhaps more emphasis could be placed on writing up nose gear shimmy events in the aircraft logbook so that it is highlighted to Maintenance before an event like ours occurs. Also; it was almost entirely by luck that I remembered to read through the AOM and found the procedures that most closely applied to our situation. Given the fact that we needed to burn down gas to land; we were not under any time constraints and had the luxury to be able to use that time to think. In a time-compressed situation; we might not have been as lucky. Emergencies in the FAR Part 121 environment are inherently distracting and busy given the amount of coordination that must occur (between Crew Members; ATC; Operations; F/As; etc.). Unless it is explicitly spelled out in the QRH; a Crew Member could easily forget to reference the AOM for procedures that could make the difference between a successful and unsuccessful outcome in an emergency situation. It would be helpful in the Table of Contents section for each chapter of the QRH to include a note of some sort reminding the Crew Member to also; if time and conditions permit; reference the AOM. It might even be more helpful to include a more extensive note that said something like; for example under the Landing Gear chapter of the QRH: 'Additional reference material is included in the AOM. This reference material includes information that may be pertinent to the following situations: Landing Gear Lever Will Not Move Up After Takeoff; Landing Gear Lever Jammed in the Up Position; ...' listing out each of the AOM sections for that particular system.Finally; we were unable to obtain Landing Data for the approach despite requesting via Dispatch. Each message that returned only contained three pages but they did not contain speeds or landing distance. We changed the destination on the Route page and then requested ICAO on the Landing Conditions page and entered Runways and changed the flaps to 40. I am not sure if we did something wrong or if there was a problem with the system or software. We ended up landing with the speeds for flaps 40 on the Init Ref page.
B737-700 flight crew and the Dispatcher involved reported a nose tire tread separation at rotation and the steps taken to safely return the aircraft to the departure airport.