Skip to content

Week 2026 / 20 · 2026-05-11 – 2026-05-17

Week 20 (11–17 May 2026): Integrity-drop measurements (consistent with GNSS degradation)

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

Affected aircraft-hour share

%4.8

Affected aircraft-hours

6,882

/ 144,057 aircraft-hours

Events

194

194 medium/high sufficiency

Position anomalies

—

No data for this week (series starts 2026-08-01)

Day by day

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

  • 3.9
    Mon
  • 5.9
    Tue
  • 5.3
    Wed
  • 4.2
    Thu
  • 4.9
    Fri
  • 4.8
    Sat
  • 4.6
    Sun

Last 12 weeks

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

%4.3%7

Highest FIRs

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

  • Ankara%26.8
  • Nicosia%6.5
  • Bucharest%6
  • Cairo%4.5
  • Sofia%4.4
  • Istanbul%2.8
  • Budapest%2.1
  • Vienna%2

Cell map of the peak day · 2026-05-12

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

  • Insufficient data
  • Low
  • Medium
  • High

Largest event of the week

Ankara

125

2026-05-11, 07–17 UTC, 11 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.

No data for this week (series starts 2026-08-01)

Findings this week

  1. In the regional scope (Türkiye and neighbours), 4.78% (6,882) of 144,057 aircraft-hours over seven days showed degraded navigation integrity; the daily rate ranged from 3.91% to 5.91%. The peak day was 12 May (5.91%), followed by 13 May (5.26%). 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): Ankara 26.8%, Nicosia 6.5%, Bucharest 6.0%, Cairo 4.5%, Sofia 4.4%.
  3. The integrity-drop event affecting the most aircraft this week was on 11 May in the Ankara FIR: 125 unique aircraft, 11 hours (07–17 UTC) (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. No position-anomaly (spoofing) data for the whole of this week: the historical spoofing series starts on 2026-08-01 and covers the focus region only. “No data” does not mean “calm”.
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.