Flight number record
DL 514
Delta Air Lines · Boston to Phoenix
- Route
- BOS → PHX
- Departs
- 17:55
- Flights
- 359
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 514, check with Delta Air Lines.
DL 514 sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.3%. The late ones land about 50 minutes behind schedule. That rests on 359 flights, with a median arrival right on schedule.
The national on-time rate over the same period is 77.3%, so DL 514 runs 6 points behind the country as a whole. Across a thousand flights that is about 61 extra late arrivals.
Key figures
On time
71.2%
Arrivals under 15 minutes late, of 351 completed flights
Avg delay
49 min
Across delayed arrivals only, not all flights
Cancelled
1.39%
National rate is 1.89%
1 hour+ late
7.4%
National rate is 8.3%
These figures cover 359 flights between September 2025 and August 2026. On-time means an arrival less than 15 minutes after the scheduled gate time, the same threshold the Department of Transportation uses in its own reports. Cancelled and diverted flights are excluded from the on-time rate and counted separately, which is why the cancellation column matters on its own.
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Schedule
When DL 514 flies
DL 514 flies BOS to PHX without a single fixed slot. Its most common scheduled departure was 17:55, used on 60 of 359 flights, with 17:50 (56 flights) and 08:10 (52 flights) next.
- Departs 17:5560 flights16.7%
- Departs 17:5056 flights15.6%
- Departs 08:1052 flights14.5%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 17:55 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.0%, and DL 514 runs 3 points better at 71.2%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
DL 514 next to BOS to PHX
Every carrier on BOS to PHX combined arrived on time 77.3% of the time across 2,012 flights, so DL 514 is 6 points behind it. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 10 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 514thin sample | 359 | 71.2% | 49 min | 1.39% | C |
| All Delta Air Lines on BOS–PHX | 429 | 71.5% | 53 min | 1.86% | C |
| All carriers on BOS–PHX | 2,012 | 77.3% | 71 min | 1.69% | B |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 514 quarter by quarter
DL 514 did not run the same all year. Its best quarter was Jan–Mar 2026 at 79.1% on time and its weakest Oct–Dec 2025 at 59.1%, a swing of 20 points on roughly 90 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202529 flights—
- Oct–Dec 202588 flights59.1%
- Jan–Mar 202689 flights79.1%
- Apr–Jun 202691 flights78.0%
- Jul–Sep 202662 flights72.4%
Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.
By weekday, DL 514 did best on Monday at 78.0% on time and worst on Saturday at 65.4%. Each day rests on about 51 flights, so a gap of 13 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 514 runs when it is late
DL 514 often beats the schedule: 89 of 351 completed flights, 25%, arrived 15 minutes or more early. The 101 late arrivals split 42 under half an hour, 33 between 30 and 60 minutes, and 26 an hour or more.
- 15+ min early89 flights25.4%
- Within 15 min161 flights45.9%
- 15–29 min late42 flights12.0%
- 30–59 min late33 flights9.4%
- 1–2 hours late18 flights5.1%
- 2+ hours late8 flights2.3%
Scale runs 0% to 100%.
Share of 351 completed flights by arrival against schedule.
8 of 58 late departures made up the time and arrived on time, 14% of them. In the other direction, 51 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at PHX.
The worst days
Worst days for DL 514
The latest arrival of the period was on 24 September 2025, 4 hours 20 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The five worst days are spread across September, October, February and May, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 24 September 2025 | 4 hours 20 minutes | Late-arriving aircraft |
| 15 October 2025 | 3 hours 31 minutes | Extreme weather |
| 15 February 2026 | 2 hours 58 minutes | Carrier |
| 18 September 2025 | 2 hours 35 minutes | Late-arriving aircraft |
| 19 May 2026 | 2 hours 18 minutes | Extreme weather |
Delay causes
Why DL 514 runs late
National Airspace System accounts for 43% of the 4,977 delay minutes carriers reported here, and the remaining four split what is left.
- 43%National Airspace System
- 28%Late-arriving aircraft
- 22%Carrier
- 7%Extreme weather
43% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 2,157 minutes out of 4,977, against a national NAS share of 21%. The split is drawn from 4,977 delay minutes reported on DL 514.
Cancellations sit at 1.39% against a national 1.89%, which is ordinary. Diversions add another 0.84%.
Connections and routes
What a delay on this flight costs
7.4% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about 50 minutes, which a normal layover absorbs.
At 2,300 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The same number turns up on one other city pair in the data, including PHX to BOS (160), but none flew often enough under DL 514 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to BOS to PHX only.
One caution: this is a thin sample. 359 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking DL 514
For a booking, DL 514 is one of the weaker ways to fly BOS to PHX: 6 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- BOS to PHX, every carrier and departure
- PHX to BOS, the return direction
- American Airlines 1057 on the same route78.1%
- Boston Logan International (BOS) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- Worst months to fly in the US, ranked by the data
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.