Indicative · based on ADS-B integrity (NIC) data
Sofia FIR (LBSR)
Integrity drop2026-10-16 11:00Z – 12:00Z · 2 h
- Scale
- Small
- Observation sufficiency
- Medium
- Aircraft affected
- 8
- In this FIR, last 30 days
- 99th of 136 events
Low navigation integrity (NIC) in adjacent cells. It does not say what caused it.
This is not a risk percentage or an observation-sufficiency value; it is only a size ranking. How is it calculated?
Opens the event's day; you choose departure and arrival.
Evidence
- Strongest moment (UTC)
- 12:00 · cell 851ee8bbfffffffOpen the strongest moment on the map
- Aircraft affected that hour
- 3 / 9 aircraft
- Scale basis
- 8 affected aircraft → Small event
- Observation-sufficiency basis
- 29 aircraft observed, 8 affected.
- Aircraft observed in hot hours
- 29 aircraft (28% affected)
- FIR
- Sofia FIR (LBSR), Bucarest FIR (LRBB)
Technical details
- Hot cell-hours
- 10(hour, cell) pairs that make up the event
- Cells
- 10
- Data source
- adsb.lol (ODbL)
- Algorithm version
- 1.6.0
Hour by hour: before, event, after
Hourly view of the event day: the event hours plus a few hours before and after. Values are the hourly share of affected aircraft across the whole published region network, not of the event's own cells; do not read them as the event's size or cause.
Before → Event → After. ○ no data: no aircraft were observed that hour; this does not mean zero interference.
| Hour (UTC) | Phase | Aircraft observed | Aircraft affected | Share |
|---|---|---|---|---|
| 08:00 | Before | 1233 | 37 | 3% |
| 09:00 | Before | 1333 | 46 | 3.5% |
| 10:00 | Before | 1389 | 47 | 3.4% |
| 11:00 | Event | 1407 | 48 | 3.4% |
| 12:00 | Event | 1351 | 43 | 3.2% |
| 13:00 | After | 1360 | 42 | 3.1% |
| 14:00 | After | 1307 | 59 | 4.5% |
| 15:00 | After | 1298 | 49 | 3.8% |
Indicative · based on ADS-B integrity (NIC) data
What we do not know about this event
- Cause: jamming, spoofing or a fault in the aircraft's avionics cannot be told apart from this data alone.
- Coverage: the data comes from a single source (adsb.lol); aircraft where there are no receivers are not seen.
- Share: the affected-aircraft count is not a share of all aircraft in the region; it covers only aircraft observed in the event's hot cell-hours.
- Reality: this is an indicator; the event has not been verified by an independent source.
Among this FIR's events in the last 30 days
This event is the 99th largest of the 136 events recorded in Sofia FIR (LBSR) over the last 30 days, ranked by affected aircraft (8 aircraft).
How is it calculated?
This is not a risk percentage and not an observation-sufficiency value. It is only a size ranking; size means affected aircraft. The 136 events are sorted by affected aircraft from largest to smallest, and this event is at rank 99. Events of equal size count as ahead of this one; low-level events are left out of the comparison.
An event crossing midnight is stored as two records. The count 136 can therefore be higher than the real number of events, and a split event can look smaller than it was; the rank can shift accordingly.
This event spans 2 FIRs. The trend covers the primary FIR (LBSR) only.
FIR-wide daily share (secondary context; not the event ranking)
Daily share of aircraft affected (affected / observed) for Sofia FIR (LBSR), over the whole FIR. A large but local event in a wide FIR may barely move this share, so it is not used to judge the event's size.
highest 6.8%
Gap: no data for the FIR that day (not zero). Marker: too few aircraft observed that day; no ratio computed.
| Day | Share | Aircraft observed | Events |
|---|---|---|---|
| 2026-09-21 | 4.9% | 15028 | 7 |
| 2026-09-22 | 3.5% | 16313 | 6 |
| 2026-09-23 | 3.1% | 17221 | 11 |
| 2026-09-24 | 3% | 17356 | 5 |
| 2026-09-25 | 3.6% | 17580 | 10 |
| 2026-09-26 | 3.7% | 19430 | 6 |
| 2026-09-27 | 3.7% | 18815 | 8 |
| 2026-09-28 | 3.9% | 16613 | 6 |
| 2026-09-29 | 4.7% | 17290 | 7 |
| 2026-09-30 | 4.5% | 18335 | 9 |
| 2026-10-01 | 3.5% | 18489 | 8 |
| 2026-10-02 | 4.4% | 18006 | 3 |
| 2026-10-03 | 5.1% | 18393 | 14 |
| 2026-10-04 | 4.4% | 18466 | 21 |
| 2026-10-05 | 5.9% | 15716 | 12 |
| 2026-10-06 | 6.8% | 14980 | 11 |
| 2026-10-07 | 6.4% | 16043 | 15 |
| 2026-10-08 | 5.8% | 16623 | 9 |
| 2026-10-09 | 4.9% | 17592 | 10 |
| 2026-10-10 | 4.9% | 19942 | 12 |
| 2026-10-11 | 5% | 19510 | 9 |
| 2026-10-12 | 4.2% | 16830 | 3 |
| 2026-10-13 | 5.1% | 15725 | 9 |
| 2026-10-14 | 5% | 15410 | 6 |
| 2026-10-15 | 5.3% | 16751 | 5 |
| 2026-10-16 | 5.5% | 16496 | 5 |
| 2026-10-17 | 4.3% | 19335 | 9 |
| 2026-10-18 | 5% | 17274 | 10 |
| 2026-10-19 | 4.3% | 17756 | 6 |
| 2026-10-20 | 5.4% | 16465 | 4 |
Secondary: 256 integrity drop event records in this FIR over the last 30 days. An event crossing midnight counts as two records, so the count is not an exact measure.
Data note: on some earlier days unfiltered records from faulty devices may be included, so shares on those days may be slightly high.
Longer history in this region
Integrity drop events with medium or high observation sufficiency for Sofia FIR (LBSR), year by year (from the days in the archive).
| Year | Events | Days with events | Observation level |
|---|---|---|---|
| 2023 | 9 | 2 / 318 | %43 · Moderate |
| 2024 | 684 | 171 / 366 | %65 · Moderate |
| 2025 | 1632 | 338 / 361 | %82 · Strong |
| 2026 | 995 | 253 / 283 | %86 · Strong |
The observation level is that year's observed aircraft-hours as a share of today's level. As the adsb.lol receiver network grew, observation grew; event counts in low-level years cannot be compared with today's. An event is one cluster of adjacent cell-hours: several unconnected clusters on the same day count as separate events and midnight splits an event in two, so the event count is not a number of separate incidents. This is not a trend or risk claim.
Method and limits
- What is this event?
- An event is a region of low navigation integrity (NIC) seen in adjacent cells over consecutive hours. It does not say what caused it (jamming, spoofing or a fault).
- What does “aircraft affected” mean?
- The number of distinct aircraft that reported low NIC in the event's hot cell-hours. It is not a count of all aircraft in the region. Observed aircraft are only those seen in the event's hot cell-hours, not all aircraft in the region. The share should therefore not be read as “the share of aircraft in the area”.
- What does observation sufficiency say?
- Observation sufficiency comes from the number of aircraft observed and the uncertainty interval of the affected share; it shows how solid the data is. It does not say what caused the event or whether it is real. A reasonable sample. “High” needs more aircraft and a narrow interval.
Indicative · based on ADS-B integrity (NIC) data · Contains information from adsb.lol contributors (ODbL 1.0) · Manzlytics GNSS