Flight profile · United Airlines
UA2647
San Francisco (SFO) to Boston (BOS) · scheduled 8:25 AM – 5:05 PM
How UA2647 performs
835 operations, February 2024 – July 2026.
UA2647 arrived on time 83.0% of the time, against 77.9% for all SFO → BOS flights, so this departure is 5.1 percentage points better than the route as a whole. Against United Airlines’ own flights on this route it is 3.6 points better.
Source: US DOT Bureau of Transportation Statistics · 835 operations, February 2024 – July 2026 · If UA2647 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA2647 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| UA2647 | 83.0% | 1.08% | -9 min | 9.0% | 835 |
| United Airlines on SFO → BOS | 79.4% | 1.01% | -8 min | 8.2% | 5,526 |
| All SFO → BOS flights | 77.9% | 1.04% | -7 min | 8.5% | 14,227 |
Source: FlyerIntel analysis of US DOT BTS data · February 2024 – July 2026
Why UA2647 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA2647 on SFO → BOS. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering February 2024 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies UA2647 comes in late, and what that does to the departure.
UA2647 is usually the aircraft’s first flight of the day: the schedule gives it a median of 7.8 hours on the ground at SFO, so its “inbound” is mostly the aircraft’s arrival the evening before.
When the aircraft came in 15 or more minutes late, UA2647 pushed back an average of 4 minutes late; when it came in on time or early, an average of 6 minutes late.
Each departure is matched to the flight the same aircraft flew into SFO just before it, using the tail number in the DOT file, 653 of 826 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| UA2647 | 23% | 9% | 13% |
| Network, same turn | 29% | 12% | 9% |
A night on the ground absorbs most of a late arrival, so a late inbound matters far less on a turn this long than on a same-day one.
The network row is every flight with a scheduled turn of 6 hours or more, usually overnight. How often UA2647’s aircraft landed 15 or more minutes late is lower than the network’s and, once the aircraft was late, how often UA2647 left 15 or more minutes late is lower than the network’s.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering February 2024 – July 2026
From pushback to gate
When it leaves SFO late, does that still matter by the time it reaches BOS?
UA2647 pushes back an average of 11.2 minutes late and reaches the gate at BOS an average of 2.4 minutes late. The 8.8 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. It spends 25.0 minutes on the taxiways at SFO, 2.0 minutes longer than a typical SFO departure in the same hour.
On arrival at BOS, UA2647 spends 6.8 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is 2.1 minutes shorter than a typical BOS arrival (9.0 min).
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached BOS. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 38,724 departures from SFO scheduled in the clock hour UA2647 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at BOS (440,886 flights), not just UA2647’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · February 2024 – July 2026
The hour it leaves SFO
Part of any flight’s record belongs to the clock rather than to the flight. UA2647 has one departure time, so this is what that time is worth.
On-time arrival rate. 38,724 departures from SFO are scheduled in the 8 AM–9 AM hour over the period, against 435,779 across the whole day.
UA2647 is scheduled out of SFO at 8:25 AM, in the 8 AM–9 AM bank. Departures from SFO in that hour arrive on time 85.2% of the time against 78.7% across the airport’s whole day — the slot alone is worth 6.5 points better before anything about this particular flight is considered.
The two airport figures cover every departure from SFO to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · February 2024 – July 2026 · Hours below 120 departures are not scored.
Other routes UA2647 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| LAX→SFO Los Angeles to San Francisco | December 18, 2025 – July 31, 2026 | 105 | 93.3% |
| ONT→SFO Ontario to San Francisco | August 19, 2025 – September 24, 2025 | 37 | — |
| BOS→EWR Boston to Newark | June 27, 2024 – September 1, 2025 | 66 | — |
| ORD→DCA Chicago to Washington | September 5, 2023 – April 30, 2025 | 52 | — |
| RNO→SFO Reno to San Francisco | February 15, 2024 – March 6, 2024 | 21 | — |
| PIT→IAH Pittsburgh to Houston | January 9, 2024 – February 14, 2024 | 37 | — |
| SFO→LAS San Francisco to Las Vegas | November 28, 2023 – January 8, 2024 | 40 | — |
| LAS→EWR Las Vegas to Newark | October 29, 2023 – December 20, 2023 | 49 | — |
| SAN→SFO San Diego to San Francisco | November 28, 2023 – December 20, 2023 | 20 | — |
| LGA→IAH New York to Houston | October 1–28, 2023 | 28 | — |
| DCA→IAH Washington to Houston | July 2, 2023 – September 30, 2023 | 82 | — |
Because the same number has served different journeys, the statistics above describe only the route UA2647 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
47 min late
against a median of 9 min early
Percentiles over 835 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering February 2024 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL400 | Delta Air Lines | 90.4% | 13 min early | 784 |
| B6434 | JetBlue | 86.2% | 11 min early | 988 |
| AS356 | Alaska Airlines | 85.1% | 9 min early | 712 |
| UA2647 this flight | United Airlines | 83.0% | 9 min early | 835 |
| UA1665 | United Airlines | 81.8% | 8 min early | 1,045 |
| B6734 | JetBlue | 76.9% | 6 min early | 810 |
| B61734 | JetBlue | 74.9% | 6 min early | 1,055 |
| DL977 | Delta Air Lines | 71.6% | 4 min early | 829 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA2647 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 835 records of UA2647 operating SFO → BOS, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
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