CH-47 Chinook variants and history, explained

The CH-47 Chinook is the Army's heavy lift cargo helicopter. A 2011 story from Program Executive Office (PEO) Aviation calls it the Army's only heavy lift helicopter and gives the start dates: first flight on September 21, 1961, and Army delivery in August 1962. The fleet has since run from the CH-47A through the B, C, D and F models, and the Army is now recapitalizing F models into the CH-47F Block II. Model letters matter to anyone who buys parts, writes training or cites a manual, so each change below carries the date of the record that reports it.

The A, B and C models

A General Accounting Office (GAO, now the Government Accountability Office) report to Congress dated February 24, 1978, PSAD-78-18, gives the early lineage. GAO wrote that the CH-47 had been the Army's primary medium lift helicopter since the early 1960s, a label the 2011 story replaces with heavy lift. Changes to the CH-47A to correct deficiencies and improve performance produced two more models, the CH-47B and the CH-47C. In 1965 the Army started product improvement programs with the contractor, Boeing Vertol. GAO found that the C model, then current, still fell short in reliability, availability, maintainability, survivability and safety.

The same report gives the fleet the Army planned to modernize: 104 A models, 74 B models and 183 C models, or 361 aircraft. About 51 earlier A models were left out because of configuration problems. The Army also planned to buy about 190 new aircraft. GAO put the combined modernization and acquisition estimate at $2.8 billion. One stated goal was to raise the A and B models to the 15,000-pound lift capability of the C model.

Modernization and the D model

The 1978 plan covered eight systems: rotor blades, the transmission and drive system, hydraulics, the auxiliary power unit, the electrical system, advanced flight controls, the cargo suspension system and engines, with engines funded separately. The Army had awarded Boeing Vertol a sole-source engineering development contract in June 1976 with a target price of $71.3 million. GAO reported a planned rate of three aircraft per month over 12 years, with the modernization contract planned for October 1980. GAO's sources included the CH-47 Project Manager's Office in St. Louis, Missouri.

The 1978 report does not use the letter D, but later Army stories tie the D model to rebuilt airframes. A 2016 South Carolina National Guard story covers the last flight of the CH-47D "Guard Copter 368" on August 16, 2016. A technical inspector quoted there said the aircraft was built after Desert Storm and was one of only three 'true D-model' aircraft, rather than an A, B or C converted into a D. A second 2011 PEO Aviation story says the D model airframe is put together with rivets. The product manager for the CH-47F, Lt. Col. Brad Killen, said that rivets and vibration produce cracks over the years.

The F model

An August 2007 Army story reports that Fort Campbell, Kentucky, received the first CH-47F at a ceremony on August 15, 2007. Company B, 7th Battalion, 101st Aviation Regiment, 159th Combat Aviation Brigade was the first and only unit with it. The story describes digital screens in place of analog gauges and an airframe designed for 10,000 flight hours. More than 100 CH-47Fs would be built from the ground up and other Chinooks rebuilt, at $30 million per aircraft.

The September 2011 PEO Aviation story says instead that the CH-47F was first delivered to Army aviators in 2009. Neither Army page explains the other's year.

The 2011 stories list what the F changed: reliability and maintainability modifications, a frame with less erosion and cracking, the Digital Automatic Flight Control System, the T55-GA-714A engine and the Common Avionics Architecture System (CAAS). Killen described the F as having a monolithic airframe. PEO Aviation's December 2020 recap reports that the Cargo Helicopters Project Office delivered 17 CH-47Fs in 2020, bringing the Army's CH-47Fs on hand to 459.

Block II and the program office

In September 2011 the Cargo Project Office was studying a new blade configuration to add about 2,000 pounds of lift in high and hot conditions. The December 2020 recap reports that the Army took delivery of the first CH-47F Block II engineering and manufacturing development prototype in September 2020.

A September 30, 2025 Army release reports a decision that authorizes Block II procurement in fiscal years (FY) 2025 and 2026. With earlier Congressionally directed buys, the Army will field Block II to two Combat Aviation Brigades. Block II is a recapitalization of existing CH-47F Block I aircraft, with a maximum gross weight of 54,000 pounds, a CAAS built on a Modular Open Systems Approach (MOSA), and commonality with the special operations MH-47G. One partner nation has committed to 60 aircraft. The release names COL Jennie Conlon as the PM of Cargo Helicopters.

The next budget moved the other way. A Congressional Research Service (CRS) report updated September 3, 2026 says the FY2027 request proposed reducing or ending funding for Army CH-47 helicopters. CRS lists the DoD discretionary request for the CH-47 at $0.33 billion and five aircraft, the House authorization at $0.71 billion and 12, and the House Appropriations Committee at $0.77 billion. The table rounds to the nearest hundredth and includes spares and repair parts.

What to check

• Which model letter does a document cover, and does it treat a rebuilt D as a new-build aircraft? A South Carolina inspector said only three were 'true D-model' aircraft.
• Does a CH-47F start date cite the August 15, 2007 Fort Campbell ceremony or the 2009 delivery year in the 2011 PEO Aviation story?
• Does a fleet figure carry its date? PEO Aviation reported 459 CH-47Fs on hand at the end of 2020.
• Is Block II described as new production, or as the recapitalization of Block I aircraft in the September 2025 release?
• Does a budget claim name the FY2027 column it uses: the $0.33 billion request, the $0.71 billion House authorization or the $0.77 billion House Appropriations figure?

Azcuna's ELLMENT for the CH-47 puts the Chinook's public technical manuals, the Army sling-load manuals and a unit's own SOPs on a laptop or tablet that answers a repairer's or flight engineer's question with no network and cites the manual and page. Azcuna submitted it as a concept white paper to the Army's xTech|Search 10 competition in October 2026.

Sources

1. 1Chinook turns 50, looks toward future · Program Executive Office, Aviation, via army.mil (September 23, 2011)
2. 2Can the Army's $2.8 Billion Program To Modernize the CH-47 Helicopter Be Improved? (PSAD-78-18) · U.S. General Accounting Office (February 24, 1978)
3. 3Last Mission for 'Guard Copter 368' · South Carolina National Guard, via DVIDS (August 25, 2016)
4. 4Chinook marks 50 years of service · PEO Aviation, via army.mil (September 28, 2011)
5. 5New Chinook Unveiled at Fort Campbell · army.mil (August 17, 2007)
6. 6PEO Aviation looks back at 2020 milestones; ready for 2021 · PEO Aviation Public Affairs, via army.mil (December 21, 2020)
7. 7Army Accelerates Capability to the Force with a Rapid Fielding Effort for Chinook Block II · army.mil (September 30, 2025)
8. 8FY2027 Defense Budget: Funding for Selected Weapon Systems (R49023) · Congressional Research Service (updated September 3, 2026)

Where this shows up in our work

• ELLMENT for the CH-47 Chinook answers a repairer's or flight engineer's question from the Chinook's manuals and the Army sling-load manuals and cites the page, with no network.
• TRACE, the offline S1000D and IETM viewer opens S1000D, MIL-STD-3001 and PDF technical manuals on a tablet with every marking intact.