Flight AA521
American Airlines flight AA521
Looking for AA521 in the air…
Charleston (CHS) to Philadelphia (PHL)
Historically, this flight arrives 15+ minutes late 14% of the time, and when it is late the delay averages 80 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 86.3%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 80 min
- Flights arriving 15+ minutes late
- Flights tracked
- 51
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 82%
- Airline (crew, maintenance, cleaning) 17%
- Air traffic control & airport 1%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Philadelphia (PHL) to Charleston (CHS)
Historically, this flight arrives 15+ minutes late 14% of the time, and when it is late the delay averages 91 minutes. It was cancelled 0.0% of the time.
- On-time arrivals
- 86.4%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- 91 min
- Flights arriving 15+ minutes late
- Flights tracked
- 44
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 55%
- Airline (crew, maintenance, cleaning) 40%
- Air traffic control & airport 5%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Philadelphia (PHL) to San Juan (SJU)
Historically, this flight arrives 15+ minutes late 28% of the time, and when it is late the delay averages 46 minutes. It was cancelled 2.7% of the time.
- On-time arrivals
- 72.2%
- Less than 15 minutes late
- Cancelled
- 2.7%
- Of scheduled flights
- Average delay when late
- 46 min
- Flights arriving 15+ minutes late
- Flights tracked
- 37
- Scheduled flights in the period
What caused the delays
- Air traffic control & airport 31%
- Late-arriving aircraft 26%
- Extreme weather 25%
- Airline (crew, maintenance, cleaning) 18%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
San Juan (SJU) to Philadelphia (PHL)
Historically, this flight arrives 15+ minutes late 43% of the time, and when it is late the delay averages 57 minutes. It was cancelled 8.0% of the time.
- On-time arrivals
- 56.5%
- Less than 15 minutes late
- Cancelled
- 8.0%
- Of scheduled flights
- Average delay when late
- 57 min
- Flights arriving 15+ minutes late
- Flights tracked
- 25
- Scheduled flights in the period
What caused the delays
- Late-arriving aircraft 54%
- Air traffic control & airport 26%
- Airline (crew, maintenance, cleaning) 20%
- Extreme weather 0%
- Security 0%
Share of delay minutes airlines attributed to each cause (BTS).
Memphis (MEM) to Phoenix (PHX)
Only 2 flights on record, which is too few for reliable odds.
- On-time arrivals
- 100.0%
- Less than 15 minutes late
- Cancelled
- 0.0%
- Of scheduled flights
- Average delay when late
- —
- Flights arriving 15+ minutes late
- Flights tracked
- 2
- Scheduled flights in the period
Show as table
| Month | On time | Flights |
|---|---|---|
| September 2025 | 88.5% | 52 |
| October 2025 | 84.1% | 44 |
| November 2025 | 100.0% | 1 |
| January 2026 | 73.2% | 44 |
| February 2026 | 50.0% | 18 |
Source: U.S. DOT Bureau of Transportation Statistics on-time data, September 2025 – August 2026. Covers flights operated by reporting U.S. carriers. About our data