EMB ERJ 170/175 ER/LR
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Training / Qualification
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
General Maintenance Action
Manuals; Company Policy; Aircraft
During preflight inspection of Aircraft X; the #2 Main Landing Gear (MLG) tire and the #3 MLG Tire were both found to have damage; affecting the airworthiness of the aircraft. The #2 MLG had an 'Open Tread Splice'; as detailed in the pilot's 'Pre and Post-Flight Tire Inspection Guide (also referred to as an Open Tread Joint). The #3 MLG tire had an approximately 1'X1' V-cut in the tire tread; with a depth of approximately 3/4'. When looking into the cut with a flashlight; the top ply cord could be seen. I notified the Captain of my findings; and we went to inspect the tires together. We both agreed that the 'Open Tread Splice' on the #2 tire fit the description and details of the 'Pre and Post-Flight Tire Inspection Guide. We also concurred; that it was the tire ply cord that could be witnessed at the bottom of the cut on the #3 tire. Maintenance Control was notified; and Maintenance came out to the aircraft several minutes later. While sitting in the cockpit; an AMT entered the cockpit to review the logbook; wanting to know who wrote the tires up. When the Captain told him that he did; he told the Captain that both tires were 'good'. The Captain shared our mutual-agreement on the condition of the tires; and the AMT refused to relent. All three of us visited the tires; and our opinions were again exchanged. However; when the AMT said he was going to sign both of the tires off; I told him that if he did; I would refuse to fly the aircraft. The AMT called for two other Maintenance techs to gather their opinions; and initially both of them surmised that each tire was good. Again; for a third time; the Captain and I shared our position on the tires. The Maintenance supervisor agreed that he would replace both tires; since the Captain and I felt that the aircraft was unsafe. However; I told him that our concern alone; should not be the reason for changing the tires. If he could produce the applicable section but in the [Maintenance Manual] that says that the conditions were acceptable; then I would be OK with taking the aircraft. However; from past experience; I knew that both of these conditions affect the airworthiness of the tires. After much discussion; the Maintenance supervisor reviewed the [Maintenance Manual]; and found the location where an 'Open Joint' in a tread cannot exceed 3mm length; nor 1mm depth (both of which were far-exceeded). For the #3 tire; he also located a section that restricts the aircraft to three additional landings; when the top ply cord becomes visible. Both tires were replaced; and the flight left with a lengthy delay.Much time was lost while the debate ensued regarding the replace the tires. If the tires were indeed good (and maintenance has no doubt that this is true); then the AMT should have been able to go to the applicable section in the [Maintenance Manual] within a couple minutes; and produce the verbiage that states the aircraft is airworthy. For the tire with cord exposed; after reviewing the [Maintenance Manual]; it was quite clear that the tire was now cycle-limited. As for the Open Tread Splice tire; our only guidance for inspecting the tires is from the Pre and Post Flight Tire Inspection Guide. Tires with an Open Tread Splice condition will continue to be written up in the same manner. These are very clear-cut discrepancies; and should be readily discerned by Maintenance; as well as our flight crews.The intent of this ASAP is not to throw anyone under the bus; but to shed light on a significant problem. Perhaps [the company] should consider training all AMTs (and Maintenance Control) on what to look for on a defective tire. Additionally; the picture in the [Maintenance Manual] is a pathetic representation of an On the Job Training (OTJ). A picture like the one attached; should be circulated through the Maintenance Department; to illustrate cause for rejection. The same type of training should be given to the pilot group; as these tires were found during a gate change; when my pre-flight inspection was conducted immediately following the last post-flight inspection. We all need to be on the same page; and have a clear understanding of the inspection criteria.
EMB-175 First Officer reported that Maintenance and the flight crew disagreed on the tire damage limits.