UAL521 is operated by BOEING CO between George Bush Intercontinental Houston Airport (KIAH) and General Edward Lawrence Logan International Airport (KBOS). The flight is most often flown by a BOEING Boeing 737 MAX 9. Typical block time is 3h 13m. SkyMeter has observed 77 legs of this flight number via ADS-B.
✈
FLIGHTS
77
last 90 days
⏱
AVG DURATION
3h 13m
tracked time
📅
SERVICE PERIOD
05/27/2025 → 08/20/2026
first → last seen
🗺
ROUTES / TYPES
12 / 5
city pairs · airframes
⚠
INCIDENT RATE
0.0%
0 flagged
Routes flown
By count · last 90 days
avg 3h 23m
·
Northeast Medical Center Hospital Heliport → General Edward Lawrence Logan
avg 1h 56m
·
Coast Guard Air Station San Francisco → Albuquerque International Sunport
Aircraft types
Equipment used on this number
Safety profile
Flagged flights · last 90 days
Go-arounds
0
Unstable approach
0
Rejected TO
0
Stall warnings
0
Overspeeds
0
Runway excursion
0
Counts represent flights with at least one occurrence of each
flag, not the total event count. See /incidents for individual events.
Recent flights
Newest 30 operations of UAL521
08/20/2026
3h 21m
No alerts
08/18/2026
3h 12m
No alerts
08/18/2026
3h 11m
No alerts
08/16/2026
3h 15m
No alerts
08/15/2026
3h 19m
No alerts
08/15/2026
2h 58m
No alerts
08/14/2026
3h 13m
No alerts
08/14/2026
3h 14m
No alerts
08/13/2026
3h 24m
No alerts
08/12/2026
3h 9m
No alerts
08/11/2026
3h 15m
No alerts
08/10/2026
2h 50m
No alerts
08/09/2026
3h 22m
No alerts
08/08/2026
3h 39m
No alerts
08/07/2026
3h 33m
No alerts
08/05/2026
3h 22m
No alerts
© SkyMeter ·
All flight data subject to ODbL attribution
·
Tracked: 90-day window