Value chain · CLM-1364
Low confidence
The evidence behind this statement is thin, indirect or second-hand. Read it as a lead to check, not as a settled finding.
In plain terms
Inside a radar aircraft in flight, crew areas got under a thousandth of the old limit from the big radars; the one weak spot was a glass dome next to a radio antenna.
The claim as recorded
A 1971 USAF survey of EC-121 early-warning aircraft reports that microwave levels aboard were not hazardous in flight: airborne readings in crew and equipment areas were more than 30 dB below the 10 mW/cm2 limit for the APS-45 height-finder and more than 35 dB below for the APS-95 search radar. The one hazardous level inside was at the glass of the navigation dome from the upper UHF communication antenna, 10 mW/cm2 at the glass, falling to 10 dB below the limit 2-3 inches inside and reaching 20 mW/cm2 at the skin with the glass removed. All other hazardous levels were outside the aircraft. Eye examinations of 27 crew and 23 controls found no lens differences.
Evidence behind this: T3, a USAF laboratory survey report (coord tier ruling 2026-10-03); it permits "the report states Y".
Scope and limits
The emitters are the aircraft's own antennas, not an external beam; frequencies of each system are not given on the pages read. Below -30 dB is below 0.01 mW/cm2 (0.1 W/m2) and below -35 dB below about 0.003 mW/cm2 (my arithmetic); the report's own table prints 0.037 for -24 dB and 0.0083 for -30 dB, both checked at render, against 0.040 and 0.010 by arithmetic, so the printed table has errors. Whether the Table VI readings were taken in flight is not stated. The dome-glass result shows a dielectric window passes field that the metal skin blocks.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF p.3 / printed ii: abstract, no hazardous microwave levels on the aircraft in flight; 27 and 23 examined (paraphrase). PDF p.18 / printed 15 (render): dB-to-mW/cm2 table. PDF p.19-20 / printed 16-17: Tables I and II, airborne crew areas below -30 dB and below -35 dB (paraphrase). PDF p.22 / printed 19: Table VI, ART-47 levels (paraphrase). PDF p.23 / printed 20: "All hazardous levels were outside the aircraft" except the navigation dome glass; 20 mW/cm2 at the skin with glass removed (paraphrase).
Basis: dB relative to 10 mW/cm2 (USAF limit); inside and outside the aircraft, ground and airborne
Related records
- Answers question
- QST-024 not published in this release
Cite this
energyaperture.com/c/clm-1364
CLM-1364, Energy Aperture, as of 1971.