To the Poster here who asked where one finds the number of, and reasons for flight diversions, it depends where you look. Here I’m addressing just the ‘mechanical’ reasons.
If your using the FAA Service Difficulty Reporting database at av-info.faa.gov/isdr/SDRQueryCon … B=NS&cD=32 it’s about 4 to 5 per week.
If your using the Google Alert feature for all diversions, returns, etc, it’s about 1 per week.
In other words, the media accounts for about 20% of what’s in that SDR database.
If you run it the other way; compare all such media accounts to SDRs filed, and with 9 carriers surveyed, the carriers are filing about 39% of what’s out there. Some filed about 25%. (A survey of 425 media incidents vs SDR data).
As that September 11, 2000 Air Safety Week article “Gaps in Database Compromise Safety Assessments” and from those FAA officials assigned to log this data had said “there is a tremendous amount missing”.