Boeing CH-47 Chinook: The Civil Heavy-Lift Profile

Two different helicopters answer to the name Chinook in United States civil work. Columbia Helicopters publishes 25,000 pounds of external load for its standard category Model 234. The surplus CH-47D that Billings Flying Service placed on a restricted type certificate in March 2025 carries 28,000 pounds at a 54,000 pound gross weight. The gap that decides projects is not payload. It is category.

The Chinook is the only tandem rotor heavy lifter in American commercial service, and it is the only civil type in the class whose capability question has a legal answer rather than a performance one. Boeing built thirteen civil Model 234 airframes. Every other Chinook flying commercial work in the United States started life as a military CH-47 and reached the civil register through the restricted category, which is a different certificate, a different rulebook, and a different set of places the aircraft is allowed to go.

This profile covers what the two civil Chinooks are, what the published numbers mean, how the hook layout differs from every single rotor lifter, and why the certification path decides which jobs each aircraft can bid. Capacity figures are quoted at the reference conditions each source states. Available payload on any given day is set by density altitude.

Thirteen airframes and a surplus pipeline

The civil Chinook began as an oil and gas aircraft. The Boeing Vertol Model 234 entered service in 1981 as a rig support transport, and according to the FAA Flight Standardization Board report for the type it was developed as the civilian version of the military CH-47. Boeing built thirteen: six Model 234LR for British Airways Helicopters, two more LR aircraft for Helikopter Service of Norway, one 234ER for Atlantic Richfield in Alaska, and three 234MLR for Taiwan. Columbia Helicopters bought the surviving western airframes across four transactions between 1984 and 1995, converted nine to the 234UT utility configuration, and acquired the type certificate from Boeing in 2006, which makes Columbia the sole holder of the only standard category Chinook design in existence.

Thirteen airframes cannot supply a national heavy lift market, and the second Chinook fleet exists because of that arithmetic. The United States Army began auctioning surplus CH-47D airframes in late 2013 as it re-equipped with the CH-47F. Vertical Magazine reported in June 2014 that fifteen aircraft went to auction, twelve of them sold to three operators, with Columbia taking six, CHI Aviation three, and Billings Flying Service three. The first ten sold for 28 million dollars in total, a range of roughly 2 to 3.5 million dollars per airframe, and the Army calculated it saved about 250,000 dollars per aircraft against the cost of demilitarising them.

Those numbers explain the shape of the market. A used surplus Chinook at 3 million dollars competes against nothing else in its capability tier on acquisition cost, and the aircraft it competes with sit in the same band described in the library's ranking of the heavy-lift helicopters actually working in the United States. What the surplus buyer does not get is the paperwork, and the paperwork is the rest of this profile.

Specifications: the two civil Chinooks

Three qualifiers belong with the table. First, the 28,000 pound figure quoted for civil Chinook capability across the trade press, including elsewhere in this library, tracks the CH-47D airframe rather than the Model 234 as Columbia configures it today; Columbia's current published external load figure is 25,000 pounds. Second, the CH-47F column is a military reference point from Boeing and is not a civil aircraft. Third, every hook figure is a structural and certificated ceiling at reference conditions, not an available payload.

Model 234 weights, speed and range are Columbia published figures reported by Vertical Magazine. CH-47D gross weight and lift capacity are Billings Flying Service figures from its March 2025 certification announcement. Engine, fuel, hook, flight rule, floor loading and seating rows are from the FAA Flight Standardization Board report for the Model 234, which sets those systems side by side against the CH-47D. CH-47F figures are Boeing published values for the military aircraft. Lift-day capacity is set by density altitude in every column.

What the tandem layout actually buys

Every conventional helicopter spends power it does not want to spend. A single main rotor produces torque, the airframe wants to rotate against it, and a tail rotor absorbs engine power holding heading instead of holding load, along with a drive shaft, a gearbox, and a blade set that all have to be inspected and can all be struck on an obstacle. The tandem answer is the same one the intermeshing rotor reaches by a different route, described in the profile of the single-seat Kaman lifter built with no tail rotor at all: two rotors turning in opposite directions cancel each other, and every shaft horsepower goes to lift.

The FAA report records the geometry precisely. The forward rotor turns counter clockwise and the aft rotor turns clockwise, both three-bladed and fully articulated, each on its own pylon at opposite ends of a fuselage roughly 51 feet long. Three consequences follow, and all three matter to a lift planner.

The first is the centre of gravity envelope. On a single rotor helicopter the load must hang close to a single point beneath the mast, and moving weight fore or aft eats into a narrow longitudinal limit. A tandem carries its lift at two widely separated points, so the usable centre of gravity range runs the length of the cabin. That is why the Chinook takes internal freight, vehicles, and long loads that would put a single rotor aircraft outside limits before it reached maximum weight.

The second is stability with weight underneath. The tandem layout resists the pendulum behaviour that governs longline work on a single rotor aircraft, which is the problem examined in the library's treatment of how slung loads start swinging and what stops them. It does not eliminate it, and the FAA report is blunt that tandem rotor aerodynamics require special emphasis in training, with settling with power and vortex ring state called out as areas where a pilot's habits from a conventional helicopter transfer badly.

The third is the cost of the geometry. Two rotors mean two transmissions, seven drive shafts, an aft vertical drive shaft, and an aircraft roughly 99 feet long with rotors turning. That footprint has to fit the site. A Chinook needs more clear space than a single rotor aircraft of similar capability, and the downwash under two overlapping discs is not a footnote: on a busy pad it drives the ground crew standards set out in what receiving crews are required to wear and where they are allowed to stand.

One hook or three

The most consequential line in the specification table is the hook row, and it is the one difference between the two civil Chinooks that changes what the aircraft can physically do rather than where it can go. The FAA report records the Model 234 as fitted with a single point cargo hook with electric and mechanical release at the flight deck, and the CH-47D as fitted with a triple point hook system with the same release arrangement.

A triple hook Chinook carries a forward, centre, and aft hook on the fuselage belly. The centre hook is the heavy station and takes the maximum single load. The forward and aft hooks work either as independent stations for separate loads or together as a tandem pair, and the tandem configuration is the capability no single rotor helicopter has. A long, rigid load slung from two points along the aircraft's own longitudinal axis cannot rotate under the aircraft and cannot start the yawing oscillation that ends a single hook lift of the same object. Bridge sections, poles, long steel, and pipe strings all fall into that category, which is why the type shows up on conductor and structure work along energised corridors and on remote heavy freight where the load is awkward rather than merely heavy.

Whichever station is used, the external load rules are the same rules that govern every other civil lift. The load is a Class B rotorcraft-load combination when it can be jettisoned and hangs free of the aircraft, the operator may not exceed the external load weight demonstrated during certification, and the combination has to appear in the rotorcraft-load combination flight manual. The mechanics of the certificate and the four load classes are set out in the external load classes and the certificate behind them.

14 CFR 133 External load certificate 14 CFR 1.1 Load class definitions

The paperwork that turns a surplus Chinook into a civil one

A military helicopter does not become a civil aircraft by being sold. It becomes one through 14 CFR 21.25, which lets the FAA issue a type certificate in the restricted category for special purpose operations. The special purposes that matter here are agricultural use, forest and wildlife conservation, which includes the aerial dispensing of firefighting materials, and external load operations. Eligibility under 21.25(a)(2) requires an aircraft that was manufactured in accordance with the requirements of, and accepted for use by, the United States Armed Forces, with a service history the FAA finds acceptable. The airworthiness certificate itself is then issued under 14 CFR 21.185(b), which repeats the same armed forces condition.

Those two clauses are the reason a Chinook built by Boeing in Pennsylvania can still fail the test. Billings Flying Service bought six CH-47D airframes from the Netherlands Defence Ministry in mid-2023. They were manufactured to United States requirements, but they were bought new by the Royal Netherlands Air Force and were never accepted for use by, nor served with, the United States Armed Forces, so 21.185(b) did not reach them on its face. The company petitioned the FAA for relief, and the petition was published in the Federal Register on 27 September 2023 with comments due 17 October. The exemption was granted in February 2024, the first of its kind for the type, and the restricted type certificate followed on 19 March 2025, covering two of the six airframes with the remaining four still in process and mission modifications scheduled for the 2025 fire season.

14 CFR 21.25 Restricted type certificate 14 CFR 21.185 Restricted airworthiness certificate

Because each restricted type certificate is issued to the applicant who did the work rather than to the airframe design, the civil Chinook has no single certificate basis. It has seven. The FAA Flight Standardization Board report lists them, and the list is the clearest picture available of who actually holds the keys to a commercial Chinook in the United States.

Certificate numbers are as listed in the FAA Aircraft Evaluation Division Flight Standardization Board report for the Columbia Helicopters Model 234, section 8.2, which names the CH-47D certificates the FAA treats as related aircraft to the Model 234. The category column is AHLH labelling: an R prefix denotes a restricted category type certificate. All seven carry the same BV-234 pilot type rating.

One detail in that report is worth pulling out for anyone budgeting crew. FAA Order 8900.1 assigns the CH-47 the civilian type rating BV-234, so a pilot qualified on the standard category Model 234 and a pilot qualified on a restricted CH-47D hold the same rating on the certificate. The FAA is explicit that the rating does not make the aircraft interchangeable: the report requires differences training and checking in both directions, and warns that the Model 234 has significant system differences in the utility hydraulics and electrical generation systems, and that it lacks the FADEC engine control the CH-47D has, which raises flight crew workload in abnormal and emergency operations.

Where category decides the job

The Model 234 is operationally suitable under 14 CFR parts 91, 133, 135 and 137, which the FAA stated formally in its 2025 Flight Standardization Board report, the first ever conducted on the type in more than forty years of service. That breadth is the whole commercial argument for a standard category Chinook, and it costs nothing to exercise.

A restricted category CH-47D operates under a narrower rule. 14 CFR 91.313 prohibits operating a restricted category civil aircraft over a densely populated area, in a congested airway, or near a busy airport, and 14 CFR 133.45 repeats the bar for external load work. Neither prohibition is absolute in practice, because Part 133 non-passenger-carrying external load operations open a path that ordinary restricted category flight does not, but the operator starts from a prohibition and has to argue out of it. A standard category Model 234 starts from permission. Both still need an approved congested area plan to work above occupied ground, which is real work described in the approval that clears a lift over an occupied area.

14 CFR 91.313 Restricted category limits 14 CFR 133.45 Operating limitations

The practical division of labour follows from that. Restricted CH-47D fleets dominate fire, timber, powerline, and remote heavy freight, where the terrain is empty and the special purpose language in 21.25 fits the mission exactly. Standard category Model 234 work reaches everything those aircraft do plus passenger transport under Part 135, instrument operations, and heavy sets over occupied ground. Thirteen airframes were ever built, nine of which reached Columbia, and Columbia sold two 234UT aircraft to a Canadian operator in August 2025. Scarcity, not capability, is what keeps the standard category Chinook off most American job sites.

The 234SP, and the problem it is trying to solve

Columbia announced a programme in February 2024 aimed squarely at that scarcity. The Model 234 Special Purpose, or 234SP, converts existing CH-47D airframes onto the Model 234 design foundation to produce, in the company's description, a fully FAA certificated transport category rotorcraft that retains CH-47D performance. Columbia had acquired eleven D-model airframes toward the programme, launched it with ROTAK Helicopter Services of Anchorage as first customer and Heliswiss International as first international customer, and targeted market entry in 2025. The announcement paired the aircraft with a Chinook Integrated Sustainment Program for commercial operators of the type.

The engineering logic is visible in the differences table above. The two civil Chinooks are the same helicopter in airframe terms and different aircraft in systems terms: different engines and fuel control, different fuel tankage, different electrical architecture, different instrument certification, different hook fit. A conversion programme that moves a surplus CH-47D onto the standard category design is a systems project, not a rebuild, and the prize is a Chinook that can fly Part 135 and work occupied ground without arguing with 91.313. No conversion had been announced as certificated at the time of writing, and nothing here should be read as saying the 234SP is available.

Planning a Chinook against thin air

Every figure in this profile is a reference-condition number. The Chinook is a strong high and hot performer, because a tandem loses no power to anti-torque and the CH-47F reaches a 20,000 foot service ceiling in Boeing's published data, but the standing planning shorthand still applies: available payload falls roughly 3 percent per 1,000 feet of density altitude, and heat and humidity move a field elevation into a higher density altitude before the aircraft leaves the pad. The mechanism and the arithmetic are worked through in how thin air eats lift capacity on the day.

Against that, the Chinook's place in the fleet is stable and easy to state. It is the tandem rotor answer at the top of the American civil capability band, it sits alongside the Air Crane in the 20,000 pound and above tier compared in the aircraft-by-aircraft breakdown of what each civil helicopter puts on the hook, and it is the only type in that tier that carries freight internally, takes passengers, slings long loads on two hooks, and lands on a ramp at the back. What separates the two civil versions of it is not the airframe. It is which certificate the airframe holds, and that answer decides the bid before anyone weighs the load. The wider capability tiers behind that judgement are laid out in what actually separates a heavy-lift helicopter from a medium one.