This methodology guide is a companion piece to the joint Washington Post Security Force Monitor investigation into U.S. support for the Saudi-Emirati led coalition. The Post-SFM joint investigation shows that only 39 air force units from coalition countries could have conducted airstrikes in Yemen, and that during seven years of war the U.S. approved contracts that likely benefited 38 of the 39 airstrike units. Using open source research the investigation confirms 19 airstrike units did serve in Yemen as part of the Saudi-Emirati coalition. In the seven years since the start of the bombing campaign in Yemen on 26 March 2022 the U.S. approved 213 contracts, out of 902 total, that likely benefited airstrike units that could have or did serve in the Saudi-Emirati coalition. As detailed in a piece in Just Security, this investigation raises troubling questions for past and future U.S. support for the air forces of coalition countries.
The guide will explain the steps taken to determine whether U.S. sales of planes, weapons or equipment likely benefited air force units that could have or did serve in the Saudi-Emirati coalition in Yemen.
Advocates and human rights researchers can use this same approach to monitor future US sales to coalition countries, as well as sales from any other country to the air forces of the Saudi-Emirati coalition.
All of the data on US sales to the Saudi-Emirati coalition can be found here.
All of the data on the aircraft, weapons, and equipment of the air forces of the Saudi-Emirati coalition can be found here.
Phase One: Establishing the units which could or did serve in the Saudi-Emirati Coalition
Our research process began with building a dataset outlining the overall organizational structure of the air forces of the nine states that have participated in the Saudi-Emirati coalition, and tracking how these have changed over time. The method, data model and encoding we have used to build up this data is described in our Research Handbook. These datasets are published on WhoWasInCommand.com (for example, Saudi Arabia).
For the Saudi-Emirati coalition our dataset describes the composition of the air forces of coalition countries starting in 2008 and 2009, years before coalition operations began in Yemen in 2015, to the present. This data draws on the books Saudi Arabia : national security in a troubled region and Middle East Air Power in the 21st Century, in addition to a large amount of other information published by media organizations, governments and civil society organizations. In particular we relied on media reporting from AirForces Monthly, Arabian Aerospace (now Times Aerospace), and the military database of the Dutch Aviation Society (also known as “Scramble”) to build out our dataset on air force units through time.
We also were able to review Arabic language sources by partnering with Mwatana for Human Rights, training researchers in our methodology and working closely with them to find relevant material in official state media sources.
As with all of our research we continually compare information contained in one source to other sources throughout the research process. This allows us to spot changes in squadron structure (i.e. the creation of a new F-15SA squadron for Saudi Arabia) or errors (i.e. a report of Qatar sending F-16s to Yemen which is not possible as Qatar did not possess any F-16s).
This research focused on squadrons, which are the basic and main operational unit of air forces around the world. Squadrons generally have 8 to 24 aircraft, usually of a single type, and play a specific role in their countries’ air force (such as a transport squadron or a reconnaissance squadron).
With datasets in place on the organizational structures of air forces, types of aircraft flown by each squadron, and their roles, our next step was to establish connections between specific squadrons and the Saudi-Emirati coalition in Yemen.
From the start of coalition operations numerous sources have reported on the types of planes sent by each country to serve in the Saudi-Emirati coalition. In summary, these sources reported the following types of airstrike capable planes were part of the Saudi-Emirati coalition:
- F-16s: from Bahrain, Egypt, Jordan and United Arab Emirates
- F-15S’s, F-15SA’s, Typhoons and Tornadoes: from Saudi Arabia
- F/A-18s: from Kuwait
- Mirage-2000s: from United Arab Emirates*
- Su-24s: from Sudan
* Qatar also sent airstrike capable Mirage-2000s to serve in the coalition but the Government of Qatar has stated none of their planes ever operated inside of Yemen. We have not found any sources to contradict this claim.
Comparing this list of types of aircraft serving in the coalition to our datasets on air force squadrons and their aircraft and roles allows us to identify the 39 airstrike squadrons which could have conducted any of the airstrikes in Yemen. As detailed in our joint investigation with the Washington Post, reviewing text sources as well as videos and photos of planes serving in the coalition enabled us to identify 19 airstrike squadrons that did serve in the Saudi-Emirati coalition in Yemen.
The table below summarizes this research, listing the country of the unit, the unit’s name, the type(s) of aircraft flown by the unit and finally whether source(s) directly state that the unit served in the coalition (indicated by “source” in the column “Coalition Service”) or that the unit flies a type of aircraft which we know was sent to serve in the coalition (indicated by “aircraft”).
|Country||Unit name||Type of Aircraft Flown||Coalition Service|
|Bahrain||1 Tactical Fighter Squadron||F-16||source|
|Bahrain||2 Tactical Fighter Squadron||F-16||source|
|Egypt||60 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||64 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||68 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||70 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||72 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||74 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||75 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||77 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||79 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||86 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||88 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||95 Tactical Fighter Squadron||F-16||aircraft|
|Egypt||97 Tactical Fighter Squadron||F-16||aircraft|
|Kuwait||25 Attack Squadron||F/A-18||source|
|Kuwait||9 Fighter Squadron||F/A-18||source|
|Morocco||Escadron de Chasse Falcon||F-16||aircraft|
|Morocco||Escadron de Chasse Spark||F-16||source|
|Morocco||Escadron de Chasse Viper||F-16||aircraft|
|Saudi Arabia||55 Squadron||F-15S, F-15SA||source|
|Saudi Arabia||6 Squadron||F-15S, F-15SA||source|
|Saudi Arabia||92 Squadron||F-15S, F-15SA||source|
|Saudi Arabia||29 Squadron||F-15SA||source|
|Saudi Arabia||7 Squadron||Tornado||source|
|Saudi Arabia||75 Squadron||Tornado||source|
|Saudi Arabia||83 Squadron||Tornado||source|
|Saudi Arabia||10 Squadron||Typhoon||source|
|Saudi Arabia||3 Squadron||Typhoon||source|
|Saudi Arabia||80 Squadron||Typhoon||source|
|Sudan||4 Bomber Squadron||Su-24||aircraft|
|United Arab Emirates||1 Shaheen Squadron||F-16||source|
|United Arab Emirates||2 Shaheen Squadron||F-16||source|
|United Arab Emirates||3 Shaheen Squadron||F-16||source|
|United Arab Emirates||71 Squadron||Mirage 2000||aircraft|
|United Arab Emirates||76 Squadron||Mirage 2000||aircraft|
|United Arab Emirates||86 Squadron||Mirage 2000||aircraft|
Additionally, this same approach identified squadrons that supported the airstrike campaign either flying reconnaissance and other support or refueling roles.
|Country||Unit name||Type of Aircraft Flown||Coalition Service|
|Kuwait||41 Transport Squadron||C-17/KC-130||source|
|Saudi Arabia||24 Squadron||A330 MRTT||source|
|Saudi Arabia||18 Squadron||E-3A||source|
|Saudi Arabia||13 Squadron||F-15C/D||source|
|Saudi Arabia||2 Squadron||F-15C/D||source|
|Saudi Arabia||34 Squadron||F-15C/D||source|
|Saudi Arabia||5 Squadron||F-15C/D||source|
|Saudi Arabia||32 Squadron||KC-130||source|
|Saudi Arabia||23 Squadron||KE-3A||source|
|Saudi Arabia||60 Squadron||Saab 2000 AEW&C||source|
|United Arab Emirates||Unnamed MRTT Squadron||A330 MRTT||aircraft|
Phase Two: Establishing Data on Planes, Weapons and Equipment
Having established all of the airstrike-capable squadrons that could have or did serve in the Coalition, our next question was whether any of these squadrons could have benefited from U.S. contracts and sales announced at any point from when the coalition bombing campaign began on 26 March 2015 to the seven-year anniversary of the war on 26 March 2020. Any U.S. contracts announced before or after these dates were excluded from our research.
We first organized all sales announced by the U.S. for the benefit of the nine coalition countries: Bahrain, Egypt, Jordan, Kuwait, Morocco, Qatar, Saudi Arabia, Sudan and the United Arab Emirates.
We exclusively used two government sources to build our dataset on sales: the U.S. Department of Defense (DOD) daily contract announcements which can be found online here, and announcements of Major Arms Sales by Defense Security Cooperation Agency (DSCA) which can be found online here.
Both these online sources have particularities that we worked around to ensure the completeness of our search for contracts: for example, the DSCA website often announces sales to the same country under multiple tags (Saudi Arabia has five different tags); and, the DOD announcements can sometimes refer to countries in multiple different ways (in particular the UAE) or even misspell the name of the country (“Jordon” rather than “Jordan”, for example). Occasionally these also contain other typos, such as a sale detailed below, to benefit Saudi Arabia’s “F-I5SA programs”. In this case this was a clear typo of F-15SA with a capital “i” in place of the “1” in F-15SA (as there is no F-I5SA plane). Finally, conducting site specific searches by country keyword as well as a restricted date range of one year, i.e. results within date range 26 March 2015 to 26 March 2016 for search string “Saudi Arabia” site:defense.gov/News/Contracts/, produced more results than a site specific search with only the country keyword, i.e. results using the search string “Saudi Arabia” site:defense.gov/News/Contracts/.
Searching through these two sources by country (including the variations of spellings) enabled us to build a dataset of all sales announced for each country of the coalition.
The next step was to determine whether squadrons that did or could have served in the Coalition benefited from any of these sales. The foundation for establishing these links was the type of plane flown by the squadron. Because every coalition country has at least two airstrike squadrons flying the same type of plane it is not possible to conclusively determine from the contract announcement itself that only a single squadron benefited. Thus our standard is “likely benefited” to show that ambiguity where a contract for F-16 sales to Bahrain could benefit both F-16 squadrons, or only one of the F-16 squadrons, we just can’t conclusively determine that based on the announcement itself.
To establish a link, sources had to provide evidence that the squadron flew the type of plane at some point during the timeframe of the contract. For example, sources show that the 29 Squadron of Saudi Arabia started flying the F-15SA in 2018. Any F-15SA sales to Saudi Arabia which started and ended before 2018 would not be coded as likely benefiting the squadron. Only sales going through 2018 and beyond would be included as likely benefiting the 29 Squadron. Then linkages between a squadron and a sale were determined based on two different metrics:
- The sale was for the benefit of a type of aircraft flown by the squadron as explicitly stated in the contract announcement. For example, the sale announced in November 2021 of AIM-120C-7/C-8 Advanced Medium Range Air-to-Air Missiles (AMRAAM) is explicit that it would “support Saudi Arabia’s Eurofighter Typhoon, F-15C/D, F-15S, and F-I5SA programs”. In this case, we consider that it likely benefited Saudi Arabian air force squadrons which flew those specific aircraft. Similarly, sales of specific aircraft to countries would also be categorized as likely benefiting squadrons flying that type of aircraft. For example, the sale announced in June 2018 for the “production of 16 F-16 V Block 70 aircraft” for Bahrain we consider that it likely benefited the Bahraini air force squadrons which flew F-16s.
- The sales included a piece of equipment or type of weapon carried by the type of aircraft flown by the squadron. We used public sourcing which linked weapons and/or equipment to types of aircraft flown by coalition countries. At the end of the guide we provide a worked example of how a sale was connected to specific squadrons.
This analysis of course also had certain restrictions which are important to note:
- Our analysis focused on sales announced after the start of the coalition’s bombing campaign on 26 March 2015 through to the seventh anniversary of the campaign on 26 March 2022. Any sale announced before the start of the coalition (even if the period covered by the contract ran through 26 March 2022 or later) or after the seventh anniversary was not analyzed by us.
- We reviewed 902 announced sales, 637 of which were not connected to the coalition air campaign. The majority of those 637 non coalition airstrike sales were PATRIOT missile defense contracts. Those 637 also included 97 sales where the services provided in a sale were expressed too generally and could not be linked to any specific squadron in our analysis (for example “engineering and technical support services” for Kuwait).
As noted above, readers can find our entire dataset of U.S. sales to members of the Saudi-Emirati led coalition here and our full list of data on aircraft flown by coalition squadrons and the various equipment and weapons carried here.
Worked example: Analysis of a contract to supply F110-GE-129 jet engines to Bahrain, Saudi Arabia and Qatar
The daily announcement of DOD contracts on 9 November 2017 includes the following sale:
General Electric, Cincinnati, Ohio, has been awarded a $643,000,000 indefinite-delivery/indefinite-quantity undefinitized contract action to provide F110-GE-129 install engines, spare engines, modernized engine monitoring system computers, over-and-above repair for government furnished property, and technical data reports. Work will be performed in Cincinnati, Ohio, with an expected completion date of Nov. 8, 2024. This contract involves 100 percent foreign military sales to Qatar, Saudi Arabia and Bahrain. Air Force Life Cycle Management Center, Wright-Patterson Air Force Base, Ohio, is the contracting activity (FA8626-18-D-0029).
The important data in the award announcement includes the contract duration, nature of products and services, and the intended recipients. We extract this information, and combine it with our knowledge of the Saudi-led coalition and its operations in Yemen to assess whether this contract could have benefitted the coalition:
|Data from contract announcement||Additional data||Assessment|
|The duration of contract is from 9 November 2017 to 8 November 2024||The two major operations by the coalition in Yemen run from 26 March 2015 to date.||The contract date range clearly overlaps with coalition operations from 9 November 2017|
|The contract provides for “F110-GE-129 install engines”||The other items included in the contract are expressed in generic terms, and cannot be tied to a specific squadron or aircraft or squadron.||Squadrons that fielded aircraft that use F110-GE-129 engines at any point between 9 November 2017 and 8 November 2024, may benefit from this contract|
|The contract is for sales to Qatar, Saudi Arabia and Bahrain.||Qatar was part of the coalition and operational in Yemen between 26 March 2015 to 5 June 2017. Saudi Arabia and Bahrain have been part of the coalition and operational in Yemen for the full duration of 26 March 2015 to date.||Bahraini, Qatari and Saudi squadrons that could have or did serve in Yemen may benefit from this contract.|
The next step is to combine the assessment with what we know about the specific aircraft in use by the squadrons of the countries named in the contract announcement.
A 2003 press release from General Electric, the manufacturer of the F110 family of engines, states that Bahrain’s F-16s use their F110 engine and that the F110-GE-129 engines were in “70 percent of the latest-generation F-16C/Ds worldwide.” No sources link that family of engines to any other type of plane flown by Bahrain in our dataset. Using our data on all Bahraini squadrons we are able to determine that the 1 Tactical Fighter Squadron and 2 Tactical Fighter Squadron both fly F-16s during the timeframe of the contract and thus likely benefited from this sale. Sources confirm that both squadrons served in the Saudi-Emirati led coalition in Yemen.
A 2020 press release from General Electric states that the F-15QA uses the F110-GE-129 engine. Using our data on all Qatari squadrons we are able to determine that the 51 Squadron likely benefited from this contract. An important note is that the 51 Squadron did not become operational until after Qatar ceased participating in the Saudi-Emirati led coalition on 5 June 2017. Therefore there is no link between the squadron and the air campaign in Yemen from any of the sources available to us.
According to an article from Arabian Aerospace published on 1 February 2011, the F-15S aircraft flown by Saudi Arabia use the F110-GE-129 engine.
Our next step is to then compare our data to see all Saudi squadrons which were flying the F-15S at some point during the contract timeframe of 9 November 2017 through 8 November 2024. Using our data on aircraft flown by Saudi squadrons we are able to determine that the 55 Squadron, 6 Squadron, and 92 Squadron likely benefited from this contract as they flew the F-15S aircraft during the contract timeframe.
In addition, another contract was announced on 25 September 2018 for the “sustainment of the Royal Saudi Air Force F-15SA.” One of the pieces of equipment for the sustainment of the F-15SA was “F110-129 engine consumables” and thus we can use this source to determine that squadrons flying the F-15SA also likely benefited from this sale. Going back to our data on aircraft we find this gives us an additional linkage for the 55 Squadron, 6 Squadron, and 92 Squadron as those squadrons also start flying the F-15SA. However, this source also allows us to link the 29 Squadron as likely benefiting from this sale as it only flies F-15SAs according to our dataset.
Sources confirm that all four squadrons served in the Saudi-Emirati led coalition in Yemen.
Tools used in this analysis
- Google Sheets
- Internet Archive Wayback Machine
Online resources mentioned in this document:
- Security Force Monitor – Research Handbook: https://help.securityforcemonitor.org
- U.S. Department of Defense – Daily contracts: https://www.defense.gov/News/Contracts/
- U.S. Defense Security Cooperation Agency – Major Arms Sales: https://www.dsca.mil/press-media/major-arms-sales
- AirForces Monthly: https://www.key.aero/airforcesmonthly
- Arabian Aerospace (now Times Aerospace): https://www.timesaerospace.aero/
- Dutch Aviation Society / Scramble – Military Database: https://www.scramble.nl/database/military