37,555 service difficulty reports for the Airbus A321 (all variants) across 39 systems (2001–2026).
Reported systems
| System | ATA | Reports | Share |
|---|---|---|---|
| Doors | ATA 52 | 7,936 | 21.1% |
| Lights | ATA 33 | 6,696 | 17.8% |
| Fuselage | ATA 53 | 6,687 | 17.8% |
| Equipment & Furnishings | ATA 25 | 5,272 | 14% |
| Stabilizers | ATA 55 | 2,252 | 6% |
| Air Conditioning | ATA 21 | 1,726 | 4.6% |
| Fire Protection | ATA 26 | 913 | 2.4% |
| Wings | ATA 57 | 671 | 1.8% |
| Landing Gear | ATA 32 | 625 | 1.7% |
| Engine - Turbine/Turboprop | ATA 72 | 589 | 1.6% |
| Auxiliary Power Unit (APU) | ATA 49 | 562 | 1.5% |
| Fuel | ATA 28 | 393 | 1% |
| Hydraulic Power | ATA 29 | 341 | 0.9% |
| Flight Controls | ATA 27 | 307 | 0.8% |
| Engine Fuel & Control | ATA 73 | 294 | 0.8% |
| Windows | ATA 56 | 228 | 0.6% |
| Engine Air | ATA 75 | 212 | 0.6% |
| Electrical Power | ATA 24 | 188 | 0.5% |
| Pneumatic | ATA 36 | 182 | 0.5% |
| Nacelles & Pylons | ATA 54 | 160 | 0.4% |
| Navigation | ATA 34 | 145 | 0.4% |
| Communications | ATA 23 | 134 | 0.4% |
| Indicating & Recording | ATA 31 | 133 | 0.4% |
| Standard Practices - Structures | ATA 51 | 115 | 0.3% |
| Engine Indicating | ATA 77 | 108 | 0.3% |
| Engine Oil | ATA 79 | 96 | 0.3% |
| Auto Flight | ATA 22 | 94 | 0.3% |
| Ignition | ATA 74 | 87 | 0.2% |
| Oxygen | ATA 35 | 85 | 0.2% |
| Engine Exhaust | ATA 78 | 84 | 0.2% |
| Ice & Rain Protection | ATA 30 | 60 | 0.2% |
| Power Plant | ATA 71 | 59 | 0.2% |
| Water & Waste | ATA 38 | 58 | 0.2% |
| Placards & Markings | ATA 11 | 27 | 0.1% |
| Starting | ATA 80 | 20 | 0.1% |
| Engine Controls | ATA 76 | 12 | 0% |
| Other | ATA 37 | 2 | 0% |
| Central Maintenance System | ATA 45 | 1 | 0% |
| Other | ATA 83 | 1 | 0% |
Report counts reflect fleet size and reporting activity, not relative safety or reliability. Source: FAA Service Difficulty Reporting System (public domain).