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Week 2026 / 40 · 2026-09-28 – 2026-10-04

Week 40 (28 September–4 October 2026): Integrity-drop measurements (consistent with GNSS degradation)

Indicative · based on ADS-B integrity (NIC) data

Affected aircraft-hour share

%3

▼ 0.1 pp vs previous week

Affected aircraft-hours

5,470

/ 179,617 aircraft-hours

Events

201

201 medium/high sufficiency

Position anomalies

218

high/medium-sufficiency events

Day by day

Each day's affected aircraft-hour share (%). Peak day in dark colour.

  • 2.6
    Mon
  • 2.9
    Tue
  • 3.4
    Wed
  • 2.9
    Thu
  • 3.1
    Fri
  • 3.4
    Sat
  • 3.1
    Sun

Last 12 weeks

Weekly share; this report is the highlighted point. Weeks without data are left blank.

%3%4.1

Highest FIRs

Regions with enough sample during the week, by affected aircraft share.

  • Damascus%9.2
  • Ankara%7.9
  • Bucharest%5.6
  • Sofia%4.4
  • Amman%3.6
  • Istanbul%3.1
  • Nicosia%2.7
  • Cairo%2

Cell map of the peak day · 2026-10-03

Each polygon is an H3 cell; “no data” does not mean calm.

  • Insufficient data
  • Low
  • Medium
  • High

Largest event of the week

Istanbul

154

2026-10-04, 06–13 UTC, 8 hours in total. The number of unique affected aircraft is shown above.

Position anomalies (spoofing) · day by day

High- and medium-sufficiency events (rule-based, focus region only); high in dark colour.

  • 16
    Mon
  • 42
    Tue
  • 46
    Wed
  • 35
    Thu
  • 13
    Fri
  • 46
    Sat
  • 20
    Sun

Findings this week

  1. In the regional scope (Türkiye and neighbours), 3.05% (5,470) of 179,617 aircraft-hours over seven days showed degraded navigation integrity; the daily rate ranged from 2.60% to 3.43%. The peak day was 3 October (3.43%), followed by 30 September (3.38%). These data do not identify the cause of any rise or fall.
  2. Share of aircraft affected by region (weekly, FIRs with sufficient observation volume): Damascus 9.2%, Ankara 7.9%, Bucharest 5.6%, Sofia 4.4%, Amman 3.6%.
  3. The integrity-drop event affecting the most aircraft this week was on 4 October in the Istanbul FIR: 154 unique aircraft, 8 hours (06–13 UTC), 47 cells (event = connected medium/high-level cell-hours). All days of the week were produced with the same algorithm version (1.5.0), so the events are comparable with one another.
  4. Position anomalies (spoofing, rule-based, focus region): 218 high/medium-confidence events this week (218 high, 0 medium); busiest day 30 September (46). There are also 18 low-confidence events and 468 jumps overlapping with low integrity; jumps coinciding with integrity loss are not counted in this headline figure; the cause is not stated. Indicator only: it states no cause.
Data period, version and scope

This report was published on 15 October 2026 and rests on the published data of that day: regional scope (Türkiye and neighbours), algorithm 1.5.0 (a single affected-aircraft definition is used: a notable share of reports showing low integrity; faulty-transmitter filter applied). This report was prepared retrospectively on 15 October 2026, after the week ended: the figures show the current reprocessed series, not necessarily what would have been published at the time. Earlier weekly reports may have been prepared with a different scope or algorithm version; reports must not be compared directly. The data come from a single source (adsb.lol); areas without receivers are invisible and “no data” does not mean “calm”. It is an indicator only: it states no cause and makes no definitive detection claim.

Open on the map

This report is based on observed ADS-B data and is not an operational navigation source. See the methodology page for the general framework.