UAL521 is operated by UMB BANK NA TRUSTEE 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 2h 50m. SkyMeter has observed 88 legs of this flight number via ADS-B.

✈
FLIGHTS
88
last 90 days
⏱
AVG DURATION
2h 50m
tracked time
📅
SERVICE PERIOD
05/27/2025 → 07/19/2026
first → last seen
🗺
ROUTES / TYPES
13 / 7
city pairs · airframes
⚠
INCIDENT RATE
0.0%
0 flagged

Routes flown

By count · last 90 days

9
KIAH → KBOS
51
avg 3h 20m · George Bush Intercontinental Houston → General Edward Lawrence Logan
KATL → KIAH
21
avg 1h 56m · Hartsfield Jackson Atlanta → George Bush Intercontinental Houston
KPWM → KIAH
3
avg 4h 3m · Portland International Jetport → George Bush Intercontinental Houston
KSFO → KABQ
2
avg 2h 8m · San Francisco → Albuquerque International Sunport
62TS → KBOS
2
avg 3h 22m · Gateway Helistop → General Edward Lawrence Logan
84TA → KBOS
1
avg 3h 21m · Allied Northborough Heliport → General Edward Lawrence Logan
KIAD → KCLT
1
avg 1h 15m · Washington Dulles → Charlotte Douglas
6XS1 → KBOS
1
avg 3h 23m · Northeast Medical Center Hospital Heliport → General Edward Lawrence Logan
US-0188 → KABQ
1
avg 1h 56m · Coast Guard Air Station San Francisco → Albuquerque International Sunport

Aircraft types

Equipment used on this number

7
B39M BOEING Boeing 737 MAX 9
41
B739 BOEING Boeing 737-900
36
B38M BOEING Boeing 737 MAX 8
24
B737 BOEING Boeing 737-700
18
A320 AIRBUS Airbus A320
11
A319 AIRBUS Airbus A319
9
B738 BOEING Boeing 737-800
3

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

30
N37506BOEING Boeing 737 MAX 9
→
07/19/2026
24m
No alerts
Replay Analysis
N819UAAIRBUS Airbus A319
→
07/19/2026
1h 34m
No alerts
Replay Analysis
N819UAAIRBUS Airbus A319
→
07/18/2026
2h 16m
No alerts
Replay Analysis
N819UAAIRBUS Airbus A319
→
07/18/2026
3h 51m
No alerts
Replay Analysis
N17402BOEING Boeing 737 MAX 9
→
07/18/2026
2h 57m
No alerts
Replay Analysis
N17402BOEING Boeing 737 MAX 9
→
07/17/2026
3h 30m
No alerts
Replay Analysis
N17402BOEING Boeing 737 MAX 9
→
07/17/2026
32m
No alerts
Replay Analysis
N17402BOEING Boeing 737 MAX 9
→
07/17/2026
3h 13m
No alerts
Replay Analysis
N37516BOEING Boeing 737 MAX 9
→
07/16/2026
3h 20m
No alerts
Replay Analysis
N57416BOEING Boeing 737 MAX 9
→
07/15/2026
3h 32m
No alerts
Replay Analysis
N17454BOEING Boeing 737 MAX 9
→
07/14/2026
3h 28m
No alerts
Replay Analysis
N37510BOEING Boeing 737 MAX 9
→
07/13/2026
3h 18m
No alerts
Replay Analysis
N37510BOEING Boeing 737 MAX 9
→
07/12/2026
9m
No alerts
Replay Analysis
N37510BOEING Boeing 737 MAX 9
→
07/12/2026
3h 27m
No alerts
Replay Analysis
N817UAAIRBUS Airbus A319
→
07/11/2026
4h 16m
No alerts
Replay Analysis
N77587BOEING Boeing 737 MAX 9
→
07/11/2026
2h 49m
No alerts
Replay Analysis
N77587BOEING Boeing 737 MAX 9
→
07/10/2026
25m
No alerts
Replay Analysis
N77587BOEING Boeing 737 MAX 9
→
07/10/2026
3h 14m
No alerts
Replay Analysis
N17566BOEING Boeing 737 MAX 9
→
07/10/2026
3h 10m
No alerts
Replay Analysis
N17566BOEING Boeing 737 MAX 9
→
07/09/2026
19m
No alerts
Replay Analysis
N17566BOEING Boeing 737 MAX 9
→
07/09/2026
3h 30m
No alerts
Replay Analysis
N17456BOEING Boeing 737 MAX 9
→
07/09/2026
2h 56m
No alerts
Replay Analysis
N17456BOEING Boeing 737 MAX 9
→
07/08/2026
25m
No alerts
Replay Analysis
N17456BOEING Boeing 737 MAX 9
→
07/08/2026
3h 22m
No alerts
Replay Analysis
N27419BOEING Boeing 737 MAX 9
→
07/08/2026
3h 20m
No alerts
Replay Analysis
N37535BOEING Boeing 737 MAX 9
→
07/07/2026
3h 32m
No alerts
Replay Analysis
N37561BOEING Boeing 737 MAX 9
→
07/06/2026
3h 26m
No alerts
Replay Analysis
N4901UAIRBUS Airbus A320
→
07/04/2026
3h 59m
No alerts
Replay Analysis
N17599BOEING Boeing 737 MAX 9
→
07/04/2026
1h 15m
No alerts
Replay Analysis
N17550BOEING Boeing 737 MAX 9
→
07/03/2026
3h 21m
No alerts
Replay Analysis
© SkyMeter · All flight data subject to ODbL attribution · Tracked: 90-day window