Melissa HanhamNOTAM Like the Present

One of the best parts of my job at CNS is working with students. They come from all over the world, speak multiple languages, and are passionate about arms control. They are also digital natives who like problem solving, and will often chase a lead with Jeffrey and me just for the love of the work.

A few weeks ago Iran posted a Notice to Airmen for the area surrounding the Imam Khomeini Space Centre. NOTAMs are cumbersome to find and decode, so I was pleased when Alex Kynerd, a first year MA candidate, took it upon himself to write an explainer and map it out on Google Earth.

NOTAM Decoding

Alex Kynerd

On February 2, 2015, Iran launched its fourth satellite, named Farj, into orbit aboard a two-stage Safir rocket from its Semnan Launch Site, according to Al-Alam News Network. The launch coincided with the 36th anniversary of the 1979 Iranian Revolution, and is the first successful satellite launch after two failed launches in 2012.

On Iran Military Forum, user “Websorber” posted about a 4-month NOTAM issued for a desert area east of Tehran near the city of Semnan. A NOTAM, or NOTice to AirMen, is a notice issued by an aviation authority alerting aircraft pilots of potential hazards over a certain location. The Imam Khomeini Space Center, the site of Iran’s test launch of the Kavoshgar-1 rocket, is located near the region covered by NOTAM A3947 issued on 28 December 2014.

Official NOTAMs are listed on Iran’s Aeronautical Information Management website. The site is updated regularly, and old NOTAM summaries are removed and replaced with newer ones.

The following is a screenshot of the cover page of the 28 December 2014 NOTAM (now replaced with more recent NOTAMs):

The same NOTAM identifier posted on Iran Military Forum is listed in the 28 December NOTAM document.

A3947 141228 1412280330/1504280830/EST



Using the International Civil Aviation Organization (ICAO) Procedures for Air Navigation Services Abbreviations and Code handbook, it is possible to decode the NOTAM from its condensed format.

The first series of characters is the NOTAM identification number. The second set of numbers is the initial effective date. The third set of numbers is the effective date range of the NOTAM, starting with the initial date YY/MM/DD/Time. After the slash is the estimated ending date for the NOTAM, YY/MM/DD/Time. The EST indicates an estimated date/time.

The second line is a reference to Reference Aeronautical Information Publication ENR (En-route) 5.1.3-9, a document available at Iran’s Aeronautical Information Services (AIS) website. The first three numbers refer to the chapters/sections of the AIP, while -9 represents the page number.

OID 90 Activated is a reference to the specific identification name and lateral limits of the location of the NOTAM. OID is a designation for a “danger area.” Here is a snip of the explanatory document:

The following image shows a screenshot of Iran’s AIP ENR5.1.3 Danger Areas Document found at Iran’s AIS website.

Under the Remarks column are several lines of more ICAO code. According to the ICAO publication, H24 indicates a 24-hour restriction over the zone. FL (or flight level) 230 corresponds to 7000 meters/23,000 feet from the ground, according to the Wikipedia page on flight level.

The code HJ may indicate from dusk to dawn or a launch is planned. Both explanations of the code HJ are given in the ICAO document. The fourth line is self-explanatory, and specifies a ground-to-air firing. Finally, IRIDIO, according to the Remarks column, may refer to the risk of interception. This acronym was not explained in the ICAO document. However, IRI also stands for Islamic Republic of Iran, according to the Civil Aviation Directives AIS and Aerodromes Service Level of Agreement (SLA). DIO may be an abbreviation of Iran’s Defense Industries Organization. The DIO is controlled by Iran’s Ministry of Defense Armed Forces Logistics, and has significantly contributed to Iran’s missile program. The DIO is a target of both US and UN sanctions.

Plotting the NOTAM Coordinates in Google Earth

The left-hand column of the AIP ENR5.1.3 Danger Areas Document indicates OID90 refers to the Semnan area. The following image from Google Earth shows the OID area, using the coordinates listed as pin locations with a polygon overlay.

Overlaying the Islamic Republic of Iran En-route Map

The Aeronautical Information Services (AIS) website also contains a map/en-route chart that shows the various airways, OID areas, and other information on Iran’s flight paths. The airway mentioned in the NOTAM above) is AWY R794, which according to the en-route chart, passes through OID90.

Zooming into OID90 gives the following image:

The positions of the VOR locations plotted in Google Earth closely match the locations on the superimposed AIP map.

On 26 January 2015, Iran’s AIS put out a new NOTAM list. The following NOTAMs were issued for the area around the Semnan facility.

First, OID51 is activated from 23-31 Jan 2015 from the hours of 3:30AM to 2:30PM between the Dehnamak VOR and Gibab as well as Airway R794 between the Dehnamak VOR and the Tabas VOR from ground to 25,000 feet above mean sea level.

Second, the lateral limits of OID41 are permanently extended over the area of the coordinates 351200N 0533500E, 350942N 0533500E, 344000N 0550000E, 351800N 0543500E.

This extends OID41 over a much larger area, including areas previously covered by OID51 and OID90. It also includes a previously uncovered triangular area northeast of OID90.

Third, the OID90 area was activated from 21 January 2015 to 1 February 2015, from the ground to an unlimited height.

This gives us a new area, larger area covered by the NOTAMs, shown below in purple. 


Alex went on to map out the Shahrud missile facility, but I’m going to save that post for a later date. Alex rightly argues that NOTAMs are useful for predicting missile activity. Restricted danger areas can also give us a hint about “other” facilities where you might not want civilian aircraft wandering.


  1. Gregory Matteson (History)

    The NOTAM format was originally intended for teletype, which is the way they came in when I was flying. The identifiers for navigation aids, airways, and warning/exclusion areas are coordinated with, and marked on published Aeronautical Charts; yes, published on paper; by the relevant national authority. The format seems just as cryptic to me, now, as they must appear to anyone else, but training and familiarity made them seem natural when I was using them.

  2. Cthippo (History)

    Impressive piece of work!

    This indicates that they are planning on launching something on those specific dates and times, but we don’t know what or to what end.

    Here’s the question I have… How does this restricted area and time compare to others? For example, what does the NOTAM footprint and duration look like for a launch out of Cape Canaveral or Vandenburg? Does the (probable) southeasterly trajectory indicate a space launch or is that just the direction of their proving grounds? The restriction “up to 25,000 feet” is also interesting. Someone smarter than me could figure out what the maximum wange of a vehicle moving on a ballistic trajectory with a peak of 25,000 feet would be and if that trajectory would land in the restricted area (I suspect it would).

  3. Websorber (History)

    Very interesting analysis by Alex. It is in line with my own analysis of NOTAMs in the Semnan area. Regarding OID90, this danger zone is, next to the activations by, NOTAMs also activated every Tuesday and Wednesday from 0430 till 0830 (GND-UNL)
    I have tried to predict SLV (or ballistic missile) launches from the Semnan area based on NOTAMs but so far I have been not very successful.
    Are there more warning messages that I do not know about or is Iran just taking the risk of unintentionally hitting an airplane with its SLVs or missiles?

  4. shaheen (History)

    Good job. Wonkish and informative.