Flight profile · United Airlines
UA1543
Newark (EWR) to San Juan (SJU) · scheduled 7:58 PM – 11:57 PM
How UA1543 performs
1,124 operations, July 2023 – July 2026.
UA1543 arrived on time 62.5% of the time, against 70.0% for all EWR → SJU flights, so this departure is 7.5 percentage points worse than the route as a whole. Against United Airlines’ own flights on this route it is 9.1 points worse.
Source: US DOT Bureau of Transportation Statistics · 1,124 operations, July 2023 – July 2026 · If UA1543 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where UA1543 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 |
|---|---|---|---|---|---|
| UA1543 | 62.5% | 1.42% | 3 min | 14.8% | 1,124 |
| United Airlines on EWR → SJU | 71.6% | 1.41% | -3 min | 10.5% | 3,397 |
| All EWR → SJU flights | 70.0% | 1.96% | -3 min | 12.0% | 6,837 |
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
Why UA1543 runs late
Where US DOT attributed the delay minutes on this flight.
crew, maintenance, boarding and fueling, all within the carrier’s control
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for UA1543 on EWR → SJU. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies UA1543 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, UA1543 pushed back an average of 36 minutes late; when it came in on time or early, an average of 14 minutes late.
Each departure is matched to the flight the same aircraft flew into EWR just before it, using the tail number in the DOT file, 605 of 1,110 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 |
|---|---|---|---|
| UA1543 | 24% | 56% | 25% |
| Network, same turn | 17% | 68% | 9% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often UA1543’s aircraft landed 15 or more minutes late is higher than the network’s and, once the aircraft was late, how often UA1543 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 July 2023 – July 2026
From pushback to gate
When it leaves EWR late, does that still matter by the time it reaches SJU?
UA1543 pushes back an average of 23.5 minutes late and reaches the gate at SJU an average of 19.6 minutes late. The 3.9 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 30.1 minutes on the taxiways at EWR, 1.0 minutes longer than a typical EWR departure in the same hour.
On arrival at SJU, UA1543 spends 4.4 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 1.8 minutes shorter than a typical SJU arrival (6.2 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 SJU. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 25,058 departures from EWR scheduled in the clock hour UA1543 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at SJU (109,607 flights), not just UA1543’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026
The hour it leaves EWR
Part of any flight’s record belongs to the clock rather than to the flight. UA1543 has one departure time, so this is what that time is worth.
On-time arrival rate. 25,058 departures from EWR are scheduled in the 7 PM–8 PM hour over the period, against 387,621 across the whole day.
UA1543 is scheduled out of EWR at 7:58 PM, in the 7 PM–8 PM bank. Departures from EWR in that hour arrive on time 66.9% of the time against 77.7% across the airport’s whole day — the slot alone is worth 10.8 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from EWR 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 · July 2023 – July 2026 · Hours below 120 departures are not scored.
By day of week
Does UA1543 run worse on particular days?
Tuesday is historically the most reliable day and Monday the least, a gap of 12.2 percentage points.
Source: FlyerIntel analysis of US DOT BTS data · July 2023 – July 2026 · Days with fewer than 120 operations are not scored.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
79 min late
against a median of 3 min late
UA1543 has an average that understates its risk: a typical arrival is 3 min late, but the worst tenth are 76 minutes worse than that. If the trip has something unmissable at the end of it, the median is the wrong number to plan against.
Percentiles over 1,124 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering July 2023 – July 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA1556 | United Airlines | 77.2% | 5 min early | 1,127 |
| UA2143 | United Airlines | 74.7% | 7 min early | 1,127 |
| UA1543 this flight | United Airlines | 62.5% | 3 min late | 1,124 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. UA1543 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 1,124 records of UA1543 operating EWR → SJU, 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
Analysis last recomputed