Editing Advanced Tactical Fighter (section)

===Request for proposals===
The [[request for proposals]] (RFP) for demonstration and validation (Dem/Val) was issued in September 1985, with proposals initially to be due that December.<ref name="USAF museum">{{cite web |url=http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2382 |title=YF-22 fact sheet |publisher=National Museum of the U.S. Air Force |archive-url=https://web.archive.org/web/20120119223134/http://www.nationalmuseum.af.mil/factsheets/factsheet.asp?id=2382 |archive-date=January 19, 2012}}</ref><ref name=Sweetman_p14>Sweetman 1991, p. 14.</ref> The top four proposals, later reduced to two to reduce program costs, would proceed with Dem/Val. The RFP not only had the ATF's demanding technical requirements, but also placed great importance on [[systems engineering]], technology development plans, and risk mitigation; in fact, these areas were deemed more important than the aircraft designs themselves as contractors would later discover in their debriefs after Dem/Val selection.<ref name="Hehs1998P2"/><ref>Mullin 2019.</ref> This was because the SPO anticipated that the ATF would need to employ emerging technologies beyond even the contemporary state-of-the-art and did not want a point aircraft design frozen at then-mature [[technology readiness level]]s; as such, the SPO needed to evaluate its confidence in a contractor's ability to effectively and affordably develop new technology. Initially, there was no requirement for flying prototype air vehicles.<ref name="A&Hp82-89"/>

At this time, the SPO had anticipated procuring 750 ATFs at a unit cost of $35 million in fiscal year (FY) 1985 dollars (~${{Format price|{{Inflation|index=US-GDP|value=35000000|start_year=1985}}}} in {{Inflation/year|US-GDP}}) with final design selection in 1989 and service entry in 1995 with a peak production rate of 72 aircraft per year. However, even at this point, the peak rate was being questioned and the entry date was at risk of slipping to the late 1990s due to potential RFP adjustments and budget constraints.<ref name="A&Hp82-89"/> Shortly afterwards, the Navy under Congressional pressure joined the ATF program initially as an observer to examine the possibility of using a navalized derivative of the ATF by adapting the design for [[CATOBAR|carrier operations]]; named the Navy Advanced Tactical Fighter (NATF), it was to replace the [[Grumman F-14 Tomcat|F-14 Tomcat]]. The Navy would eventually announced in 1988 that they would procure 546 aircraft under the NATF program at a peak rate of 48 per year.<ref name=Miller_p14>Miller 2005, p. 14.</ref><ref name="A&H1998p235-239">Aronstein and Hirschberg 1998, pp. 235-239.</ref>

The Dem/Val RFP would indeed see some changes after its first release that pushed the due date to July 1986; in December 1985, following discussions with Lockheed and Northrop, the two contractor teams with prior stealth experience from the ''Have Blue''/F-117 and ATB/B-2 respectively, all-aspect stealth requirements were drastically increased. Furthermore, the [[Packard Commission]], a federal commission by President [[Ronald Reagan]] to study [[Department of Defense]] procurement practices, had released its report in February 1986 and one of its recommendations was a "fly-before-buy" competitive procurement strategy that encouraged prototyping. The ATF SPO was pressured to follow the recommendations of the Packard Commission, and in May 1986, the RFP was changed so that final selections would involve flying prototypes.<ref name="Mullin2012p18-21"/> Because of this late addition due to political pressure, the prototype air vehicles were to be "best-effort" machines not meant to perform a competitive flyoff or represent a production aircraft that meets every requirement, but to demonstrate the viability of its concept and mitigate risk. The increased costs associated with aircraft prototyping was also partly why the number of Dem/Val finalists was reduced from four to two.{{refn|group=N|The JAFE program, later renamed the ATF Engine (ATFE) program, were modified around this time as well to provide flightworthy examples for the prototypes, and the SPO would assume management of the ATF engine effort in February 1987.<ref>Aronstein and Hirschberg 1998, pp. 208, 215-217.</ref>}}<ref name="A&Hp82-89">Aronstein and Hirschberg 1998, pp. 82-89.</ref><ref name="ATF_chief_eng"/>

[[File:Lockheed Model 090P 300x172.jpg|thumb|left|Lockheed's submission for Dem/Val RFP. The eventual YF-22 would have a completely different configuration.]]
In July 1986, proposals were provided by [[Boeing]], [[General Dynamics]], [[Grumman]], Lockheed, Northrop, [[McDonnell Douglas]], and [[Rockwell International|North American Rockwell]]; Grumman and North American Rockwell would drop out shortly afterwards.<ref name=Miller_p14-9/> Because contractors were expected to make immense investments of their own — likely approaching the amount awarded by the contracts themselves when combined — in order to develop the necessary technology to meet the ambitious requirements, teaming was encouraged by the SPO. Following proposal submissions, Lockheed (through its [[Skunk Works]] division), Boeing, and General Dynamics formed a team to develop whichever of their proposed designs was selected, if any. Northrop and McDonnell Douglas formed a team with a similar agreement.<ref>Goodall 1992, p. 94.</ref><ref name="A&H1998p164"/>

[[File:Northrop ATF DP110 300x258.jpg|thumb|Northrop's submission for Dem/Val RFP. In contrast to Lockheed, note the great similarity to the eventual YF-23.]]
On 31 October 1986, Lockheed and Northrop, the two industry leaders in [[stealth aircraft]], were selected as first and second place respectively and would proceed as the finalists. Noteworthy is the divergent approach of the two finalists' proposals. Northrop's proposal leveraged its considerable experience with stealth to produce a refined and well-understood aircraft design that was very similar to the eventual flying prototype.<ref name="Chong2016p237-238">Chong 2016, pp. 237-238.</ref><ref name="Metz2017p25-27">Metz 2017, pp. 25-27.</ref> While Lockheed also had extensive prior stealth experience, their actual aircraft design was quite immature and only existed as a rough concept that would have to be extensively redesigned; instead, Lockheed primarily focused on systems engineering and [[trade study|trade studies]] in its proposal, which pulled it ahead of Northrop's to take top ranking.<ref name="Mullin2012p18-21">Mullin 2012, pp. 18-21.</ref><ref name="Hehs1998P2">Hehs 1998, Part 2.</ref> The two teams, Lockheed/Boeing/General Dynamics and Northrop/McDonnell Douglas, were awarded $691 million [[fixed-price contract#Firm Fixed Price Contract (FFP)|firm fixed-price contract]]s in FY 1985 dollars (~${{Format price|{{Inflation|index=US-GDP|value=691000000|start_year=1985}}}} in {{Inflation/year|US-GDP}}) and would undertake a 50-month Dem/Val phase, culminating in the flight test of two technology demonstrator prototypes, the [[Lockheed YF-22|YF-22]] and the [[Northrop YF-23|YF-23]]. Pratt & Whitney and General Electric would also receive $341 million (~${{Format price|{{Inflation|index=US-GDP|value=341000000|start_year=1985}}}} in {{Inflation/year|US-GDP}}) each for the development and prototyping of the competing engines (designated YF119 and YF120 respectively), and the JAFE propulsion effort would later be renamed ATF Engine (ATFE) and directly managed by the ATF SPO.<ref name=Miller_p19-0>Miller 2005, pp. 19–20.</ref><ref name="A&H1998p164"/>