Value chain · CLM-1290
In plain terms
A 1963 US aviation agency study set the safe level for an aircraft flying through a radar or radio beam at the then human exposure limit, 10 milliwatts per square centimetre, and ten times lower for aircraft carrying explosive devices.
The claim as recorded
The US Federal Aviation Agency's 1963 report RD-64-1 concludes, from a literature study and its own analysis, that aircraft not carrying electroexplosive devices "may be safely exposed to average power densities of 10 milliwatts per square centimeter (10 mw/cm2) or less", and that aircraft carrying such devices may be safely exposed, under some conditions, to 1 mW/cm2. The 10 mW/cm2 figure is the accepted limit for human exposure, which the report also judges safe for fuel vapour (no ignition below about 25 mW/cm2 in a vapour-air mixture ignitable by minimum-energy sparks) and for lower-frequency avionics. The 1 mW/cm2 figure is the report's own choice, made because no limit for aircraft carrying such devices was given in the literature.
Evidence behind this: T3, a government agency report with a named author and a stated method (literature search plus analysis); the report itself says it is not a standard or regulation.
Scope and limits
An analysis from 1960s literature, not a test: the abstract recommends "that experiments be undertaken to verify analyses in this report". The title page says it "does not, in itself, constitute a standard, specification or regulation". The human limit is the 1963 Armed Services figure, not a current one. In W/m2 the criteria are 100 and 10, and the fuel threshold about 250 (our conversion). For scale only (our arithmetic): the 1980 SPS reference beam peak of 230 W/m2 at the rectenna centre (CLM-1204) is 2.3 times the 100 W/m2 criterion. The report concerns radar and radio beams, not a power beam, and states no frequency range or exposure duration for the criterion. The copy held ends at printed p.12, so the report's conclusions section is not read; the conclusion here is from the abstract.
What it assumes
No assumptions are recorded against this claim.
Where it comes from
PDF 5 [iii], abstract: aircraft not carrying electroexplosive devices "may be safely exposed to average power densities of 10 milliwatts per square centimeter (10 mw/cm2) or less"; those carrying them "may be safely exposed, under some conditions, to power densities of 1 mw/cm2". PDF 7 [2]: humans "should not be exposed to microwave radiation of average power density greater than 10 mw/cm2"; for fuel vapour "no ignitions occur in fields of average power density less than about 25 mw/cm2"; the report judges the human-exposure limit of 10 mW/cm2 average power density safe for aircraft crossing radar and radio beams (paraphrased) PDF 14 [9]: "Since no limit is given in the literature", aircraft carrying EEDs "should not be exposed to fields of greater average power densities than 1 mw/cm2"; footnote "100 w/m2 = 10 mw/cm2".
Basis: mW/cm2 average power density (W/m2)
Cite this
energyaperture.com/c/clm-1290
CLM-1290, Energy Aperture, as of 1963-12.
Connected records
Other published records linked to this one. A list, not a judgement.