Table 2-15. Number of Pilot-Reported Near Midair Collisions (NMAC) by Degree of Hazard

Table 2-15. Number of Pilot-Reported Near Midair Collisions (NMAC) by Degree of Hazard

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  1980 1985 1990 1991 1992 1993 1994 1995 1996 1997 1998R 1999
Degree of hazard                       
Criticala 118 180 74 52 46 35 47 32 26 31 22 24
Potentialb 319 423 266 197 195 158 139 139 101 105 97 100
No hazardc 122 133 114 99 70 61 71 63 55 70 52 55
Unclassifiedd 9 22 0 0 0 0 0 0 0 0 0 0
Opene 0 0 0 0 0 0 18 4 12 30 37 73
Total 568 758 454 348 311 254 275 238 194 236 208 252
NMAC involving aircraft                       
operating under 14 CFR 121f U U 121 101 72 60 63 43 49 81 64 63

a A situation where collision avoidance was due to chance, rather than an act on the part of the pilot. Less than 100 feet of  aircraft separation would be considered critical.
b An incident that would probably have resulted in a collision if no action had been taken by either pilot.  Less than 500 feet would usually be required in this case.
c When direction and altitude would have made a midair collision improbable, regardless of evasive action taken.
d No determination could be made, either due to insufficient evidence or unusual circumstances.
e Incidents that are still under investigation.
f Before Mar. 20, 1997, 14 CFR 121 applied only to aircraft with more than 30 seats or a maximum payload capacity of more than 7,500 pounds. Since Mar. 20, 1997, 14 CFR 121 includes aircraft with 10 or more seats that formerly operated under 14 CFR 135. This change makes it difficult to compare pre-1997 data with more recent years' data.

KEY: R = reversed; U = data are not available.

NOTE: Includes air carriers, general aviation, military, and other aircraft involved in public-use operations.

SOURCES: U.S. Department of Transportation, Federal Aviation Administration, Aviation Safety Statistical Handbook Annual Report (Washington, DC: Annual issues). NMAC involving 121 aircraft: Ibid. Air Traffic Resource Management, personal communications, Mar. 18, 1999 and May 22, 2000.