Date: 201905
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Parked
Aircraft component: Tires
Component problem: Improperly Operated
Reporter organization: Air Carrier
Reporter function: Technician
Human factors: Confusion; Training / Qualification; Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Maintenance
When detected: Routine Inspection
Result: General Maintenance Action
Contributing factors: Aircraft; Company Policy; Manuals; Procedure
Primary problem: Manuals

Narrative: Aircraft X came in the gate from the islands; which was about 2 hour turn. While I was following the check card; the nose tire where not at max cold pressure and had the est. at #1 195; and #2 200 psi. The main tires where not reading max cold pressure at or above 205. #1 tire about 195 to 200; #2 reading 190; [and] #3 around at least 200 and for the same with #4 tire at 200. This was checked about a 45-60 minutes after the plane had landed. In this situation it seems to be confusing on what to do? 1. All tire pressures were not at max or higher. 2. The planes are coming to ZZZ to T-1 area for ETOPS (Extended Twin Operations) check and we are seeing more planes with these lower tire pressure issue. We are becoming more alarmed that something is wrong. 3. The tires felt cool; but still consider as a hot tire check. Not passing the 2-hour time limit. 4. The tire pressure gage is within calibration date. 5. To find the taxi weight and tire; find the minimum service pressure? What does that mean to Maintenance? (Reference AMM (Aircraft Maintenance Manual) 12-15-51-780-802 Par. G item 4. A). 6. Please see: AMM task 12-15-51-780-802 hot tire check; AMM task 12-15-51-780-801 tire check and servicing. 7. As the same aircraft is scheduled multiple legs of ETOPS flights in a row with less than two hours for the tires to cool down; it is a violation of the maintenance practice as the AMM states the following: (4) If it is not possible to wait the recommended two hours for the tires to cool down before the airplane is dispatched; you can use this task as an alternative inspection just prior to dispatch. NOTE: The hot tire pressure check procedure is intended for occasional use only. It is not intended to be used as permanent alternative method to performing the more accurate cold tire checks. The more accurate cold tire pressure check method should be used as frequently as possible to avoid possible tire service life problems such as tread losses and carcass ruptures. The question remains; what is the 'intended for occasional use only'? 8. We are concern[ed] [about] what we should be doing here? 9. On this aircraft I brought all pressure up to max cold pressure 208 for the nose and 205 for the main. Are the checks being done right? Like 1svc (Service) / 2svc: ETOPS: phase check so on? Please get back to us on this and understanding the hot tire AMM as well as cold tire pressure. These tires should not be reading that low after landing; normally we would see them around 230+ for the main and about 5 to 10 higher the nose.




Synopsis: Maintenance Technician reports that 737-800 tire pressures are reading low after landing.