The missions beyond standard construction

Specialized Heavy Lift: How Sky Crane Services and Helicopter Crane Missions Work

Sky crane services carry cargo on an external hook under FAA Part 133 authority. The largest published hook figure among the aircraft on this page is 28,000 pounds, for Columbia's Model 234 Chinook. This hub covers the work beyond standard construction: disaster response, certification drop testing, and freight to roadless country, along with the cases where a ground crane is the better answer.

Read the Part 133 Reference
28,000 lb The largest published hook figure in the fleet table, on Columbia's Model 234
Part 133 The FAA rule governing every commercial external load flight
Class A to D Four rotorcraft load combination classes, each separately authorized

The definition

What are sky crane services?

A sky crane, also called a helicopter crane or aerial crane, is a rotorcraft configured and certificated to carry cargo on an external hook rather than inside a cabin. In the United States, commercial external load work is flown under 14 CFR Part 133, the FAA's rotorcraft external load rule, which covers the aircraft, the pilot, the rigging, and the operational plan together.

That distinction separates two kinds of flying. Charter work moves people and freight inside the aircraft. External load work engineers the load: checking its weight against the aircraft's hook limit and its performance in the expected conditions, designing rigging to the standard that applies to each component, and obtaining operation-specific approval before a load crosses a congested area. This hub covers the second kind.

Specifically, it covers the missions that sit above and beyond routine aerial construction and utility and infrastructure work: the operations where the load is one of a kind, the site is unreachable, the clock is set by a federal emergency declaration, or the mission itself is the test.

The fleet tiers

The civilian ceiling: 28,000 pounds on the hook

The heaviest published hook figure among the aircraft below is 28,000 pounds, for the tandem rotor Model 234 Chinook. The rest of the table runs down from there, and matching the airframe to the load is the first engineering decision of every mission. The published figures rest on different measurement bases, so each one has to be read with its source.

Tandem rotor Chinook helicopter in flight with full rotor arcs against open sky
The Chinook family defines the 28,000 pound civilian heavy lift ceiling.
Aircraft Max longline capacity Precision hook limit Airworthiness category Picks per hour Altitude notes
BV-234 Chinook28,000 lb (Vertical: Model 234 UT/LR, on the hook)Not published hereNot published hereNot published here15,000 ft service ceiling
CH-47D ChinookNot published hereNot published hereNot published hereNot published hereNot published here
S-64F Skycrane25,000 lb (Erickson: maximum external cargo)Not published hereNot published hereNot published here8,100 ft (2,475 m) service ceiling
CH-53D Sea StallionNot published hereNot published hereNot published hereNot published here16,750 ft service ceiling
S-70M Black HawkNot published hereNot published hereNot published hereNot published here20,000 ft ceiling; 6,200 ft OGE hover

Each capacity cell carries the figure its named source publishes, and those sources state different measurement bases, so the figures are not interchangeable lift-day allowances. Precision placement limits, certification category, and cycle rate are not published here: cycle rate belongs to the operator's estimate against the actual pick list, and category belongs to the individual aircraft's certification record. Allowable load depends on the specific aircraft and on lift-day conditions, among them density altitude, the air density at the site expressed as an altitude. No single percentage describes that effect across airframes; the FAA Helicopter Flying Handbook, chapter 7 explains how conditions change performance. The altitude notes in the last column carry no source on this page; check them against the specific aircraft's flight manual before planning to them.

Certification decides where an aircraft can work, and the answer belongs to the individual aircraft rather than to the model name. Section 133.45(d) prohibits rotorcraft type certificated in the restricted category under ยง21.25 from external load operations over densely populated areas, in congested airways, or near a busy airport with passenger transport operations. Section 133.33(d) sets out the operation-specific plan and the approval that congested-area work requires, coordinated with the responsible Flight Standards office, and an approved plan does not remove an aircraft's certification restrictions. Settle the question against the aircraft's own certification record early, because variants of one model do not all carry the same category. The external load operations reference page covers the certificate and the plan in full.

The certificate boundary

What distinguishes a Part 133 operator from a charter company?

A Part 133 Rotorcraft External Load Operator Certificate is a separate FAA certification from the Part 135 charter certificate that governs passenger and cargo transport inside the aircraft. The boundary is the fuselage wall: cargo on a hook is Part 133 work, people and freight in the cabin are Part 135 work. A charter company can fly a construction crew to a site under its own certificate. Slinging a transformer onto a pad takes the Part 133 certificate.

Part 133 defines four rotorcraft load combination classes, and the operator flying the mission has to hold the class the work requires:

  • Class A: the load cannot move freely, cannot be jettisoned, and stays above landing gear level. Fixed racks and baskets.
  • Class B: the load is jettisonable and lifted free of land or water. This is the workhorse class for every heavy external lift described on this hub.
  • Class C: the load remains in contact with land or water, such as wire pulling during transmission line stringing.
  • Class D: human external cargo (HEC), carrying a person outside the aircraft under additional equipment and approval requirements in the rule.

The class structure decides release mechanisms, rigging requirements, pilot qualification, and what the operator is authorized to fly. Check the authorized classes against the work using the certificate itself rather than a description of the company. The external load operations page is the full plain language reference on the certificate, the load classes, and congested area plans.

The government stack

What standards govern federal and military mission work?

Specialized heavy lift regularly serves government buyers, and government work adds its own compliance requirements on top of Part 133. For US Army Corps of Engineers missions and most federal construction support, site safety runs to USACE EM 385-1-1, the Corps' safety and health requirements manual. Contractors bidding federal work should plan for activity hazard analyses, lift plans, and rigging documentation built to that standard, and should confirm that the aviation company on the job works to it as well.

Beyond the regulatory floor, buyers also vet aviation companies through third party safety audit programs such as ARG/US and Wyvern, alongside contractor prequalification systems. Ask for safety management system documentation, audit history, and the insurance certificates that apply to this scope of work, then keep that review attached to the named flight operator, the company whose certificate covers the flight. A coordinator arranging the mission can assemble the package; the documents still have to belong to the company flying the load.

EM 385-1-1 USACE safety manual 14 CFR 133 External load certificate

The reading paths

Helicopter crane and aerial crane mission profiles

Mission profile 01

Disaster relief

When a hurricane or flood severs road and grid access, rotorcraft carry the logistics. Generator sets, utility poles, water, and temporary bridge components move by hook while ground routes are still being cleared. Standby and readiness contracts set out how quickly assets mobilize and on what terms, and the work coordinates with FEMA emergency support functions and Corps of Engineers mission assignments, including operations inside temporary flight restriction airspace. Full detail on mobilization structures and first 72 hour load priorities is on the disaster relief page.

Field study
Tandem rotor helicopter holding a hover over a desert test range with an instrumented test article suspended on a single cable

Mission profile 02

Drop testing

The least common mission profile on this hub: precision release of instrumented test articles for certification and R&D programs. Airframe crashworthiness articles, parachute and airdrop systems, and container qualification tests all need an aircraft that can hold a release point in space and a crew working to a release envelope, a positioning tolerance, and a telemetry plan. The same Part 133 Class B jettison arrangements that protect a construction lift make a controlled, repeatable test release possible. The drop testing page details release profiles, range coordination, and data package deliverables.

Field study
Twin engine helicopter staged on an offshore platform helideck with a gas flare burning behind it

Mission profile 03

Remote site freight

Aerial trucking for roadless country. When building a road would cost more than the payload is worth, external load freight replaces months of ground logistics with flight days: camp modules, fuel, telecom equipment, and bridge components delivered to sites no truck can reach. The remote site freight page walks through the full cost structure anatomy, including hourly rate, ferry time, fuel, and standby, so planners can rough out an estimate from published industry figures.

Field study

Mission profile 04

External load operations

The discipline underneath everything else on this site. The external load operations page is the canonical Part 133 reference: the certificate, all four load classes, congested area plans, rigging requirements, and the physics of flying a load on a line. Every page on this site links to it because every mission profile described here is built on it.

Pillar reference

The editorial standard

The legacy behind this site

American Heavy Lift Helicopters is an information project built by rotor wing enthusiasts, written for the people who estimate, plan, and manage lifting work. That readership sets the editorial standard: name the rule, the standard, or the manufacturer behind a figure, say plainly where something is not published, and follow a supported fact through to the decision it changes. A claim that cannot be sourced comes out of the page rather than getting softened into a possibility. The same standard applies to the comparisons that end with a ground crane.

Read the Full Story

The honest comparison

When the ground crane wins

A ground crane is the better engineering outcome when the lift is long duration and steady state, when a single pick exceeds the published capacity of the aircraft available, or when the site offers clear crane access without closure costs or a long setup. Compare both proposals against the same scope, including the jobs where the crane is the lower-cost answer. The full comparison model, including every scenario where the crane wins, is published in the helicopter vs. crane total cost analysis.

Where the aircraft fits the work, the case usually rests on access: reaching positions no crane can set up to serve, and moving between them without repositioning a machine. That advantage still carries a ground plan of its own. The operation needs a pickup area, a protected flight route, and whatever ground protection its approval requires, and those costs belong beside the flight hours in the comparison rather than outside it.

Read the Total Lifted Cost Analysis See the US Heavy Lift Fleet Ranked
Ground crane rigged on a construction site, the baseline case every heavy lift comparison starts from
When access is clear and the lift is steady state, the honest analysis points to the crane.

The manifest

Where to go deeper

Each mission profile above has a dedicated analysis: disaster relief, drop testing, and remote site freight. For the regulatory foundation under all of them, start with the external load operations reference, then the helicopter vs. crane total cost analysis for the decision framework. New analyses in this series are announced through the mailing list.

Frequently asked questions

Sky Crane Services, Answered

Published figures differ by aircraft and by what the specification measures. Vertical reports 28,000 pounds on the hook for Columbia's Model 234, and Erickson lists 25,000 pounds of maximum external cargo for the S-64F. Those are published maximums rather than lift-day allowances. The operator establishes the allowable load for the specific aircraft and the conditions on the day, including fuel state and rigging weight.

FAA Part 133 governs the flight operation itself. On Corps of Engineers and most federal construction missions, USACE EM 385-1-1 governs site safety, lift plans, and rigging documentation. Government test and range work adds the range's own safety requirements. Some buyers also ask for third party aviation audit credentials such as ARG/US or Wyvern vetting, so confirm which ones a particular contract requires instead of assuming a standard set.

There is no universal response time. Mobilization depends on where the aircraft is based, the ferry distance to the incident area, and what the contract already covers. Standby and readiness agreements state the notice period and the terms that apply to it, and pre-positioning agreements with utilities and agencies move credentialing, insurance, and airspace coordination ahead of the event. Take the committed response time from the agreement rather than from a published example.

A charter company holds a Part 135 certificate to carry passengers and cargo inside the aircraft. A Part 133 operator holds a separate FAA Rotorcraft External Load Operator Certificate covering loads carried on an external hook, including jettison systems, rigging requirements, load class authorizations, and congested area plans. Slinging cargo requires the Part 133 certificate, held by the company that flies the load.

The process starts with verified weight and center of gravity data, then matches the load to an airframe with margin in the expected conditions. The rigging design names the standard that applies to each component along with the inspection criteria that follow from it, attachment points are validated, and unstable geometry is controlled with drogues or tag lines. Under 14 CFR 91.3 the pilot in command has final authority over the operation of the aircraft, which a schedule argument does not override.

Certification decides it, aircraft by aircraft. Section 133.45(d) prohibits rotorcraft type certificated in the restricted category under 21.25 from external load operations over densely populated areas, in congested airways, or near a busy airport with passenger transport operations. Congested area work under 133.33(d) needs an operation-specific plan and FAA approval, and that approval does not remove a certification restriction. Check the individual aircraft's certification record, because variants of one model do not all carry the same category.

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