AF Form 4013: Modified CARP Solution – Download & Guide

AF Form 4013: Modified CARP Solution – Download & Guide – The AF Form 4013, officially titled Modified CARP Solution, is a critical U.S. Air Force form used in Computed Air Release Point (CARP) procedures for airdrop operations. It supports accurate delivery of personnel, equipment, supplies, and cargo via parachute from aircraft such as the C-130 and C-17. Aircrew rely on it (or MAJCOM-approved mission planning software) as a specialized tool for modified CARP calculations, particularly when standard basic solutions need adjustment for specific mission parameters.

This form helps compute forward travel and drift effects to determine the precise release point, ensuring loads land on or near the intended Point of Impact (PI) on the drop zone (DZ). It is governed primarily by AFMAN 11-231, Computed Air Release Point Procedures (current as of the 18 November 2020 edition).

What Is CARP and Why Is the Modified CARP Solution Needed?

Computed Air Release Point (CARP) is the calculated position in the air where the first item (paratrooper, bundle, or heavy equipment) must be released so that wind drift and forward motion bring it to the desired impact point on the ground. The CARP system relies on average parachute ballistics, dead reckoning, drop altitude, winds, temperature, and terrain elevation.

The basic CARP solution (often documented on AF Form 4018) uses detailed MB-4 computer (“whiz wheel”) calculations or aircraft mission computers (MC) for C-17 and C-130J. The modified CARP solution on AF Form 4013 simplifies this for certain scenarios using the forward travel formula:

D = K × A × V

  • D = Drift effect (in yards or meters)
  • K = Average constant value specific to the type of load/parachute
  • A = Drop altitude in feet AGL divided by 1,000
  • V = Ballistic wind velocity in knots

This approach is especially useful for providing data directly to airdrop mission computers (such as SCNS, INS, or GPS systems) and for quick planning or in-flight adjustments.

Primary method today: MAJCOM-approved mission planning software (MPS). Aircrew must verify all MPS outputs. The manual method with forms like AF Form 4013 or 4018 serves as backup.

When and How AF Form 4013 Is Used?

Aircrew use the Modified CARP Solution (AF Form 4013) for:

  • Low-altitude airdrops of non-gliding canopies (personnel, Container Delivery System (CDS), heavy equipment).
  • Situations requiring simplified forward-travel-based computations.
  • Inputting data into aircraft navigation systems for automated or semi-automated releases.
  • Training and contingency operations where full basic computations may be adjusted.

It is not the default for all drops—refer to AFMAN 11-231 Chapters 3 and 4 for basic vs. modified procedures, and cross-reference with AFI 13-217 (or DAFMAN 13-217) for drop zone operations.

Key supporting elements include:

  • Drop altitude (AGL and true/MSL)
  • Terrain/point of impact elevation
  • Winds (ballistic wind)
  • Parachute type and load specifics
  • Temperature and density altitude corrections

The form captures call sign data, drop data, organization, results, preflight altimeter setting, and other mission-specific details to produce a usable CARP.

Note: For modern C-130J and C-17 operations, many CARPs are generated directly in the mission computer using embedded parachute ballistic databases. Paper forms like AF Form 4013 are still referenced for verification, training, or when manual entry is required.

How to Download the Official AF Form 4013?

The current official PDF is available directly from the Air Force e-Publishing site:

→ Download AF Form 4013 PDF: https://static.e-publishing.af.mil/production/1/af_a3/form/af4013/af4013.pdf

Always use the latest version from e-publishing.af.mil and check for any superseding guidance in AFMAN 11-231 or MAJCOM supplements. Forms are for official government use in accordance with applicable Air Force instructions.

  • AF Form 4018: Computed Air Release Point Computations (basic solution).
  • AF Form 4015: High Altitude Release Point Computation.
  • AFMAN 11-231: Primary manual for CARP procedures.
  • DAFMAN 13-217 / AFI 13-217: Drop Zone and Landing Zone Operations (DZ sizing, marking, control, and safety).

Aircrew must brief all planned release points regardless of computation method. Documentation requirements vary—MC-calculated CARPs on certain platforms may reduce or eliminate paper forms.

Best Practices for USAF Aircrew

  1. Verify, Verify, Verify: Even with software, cross-check against manual methods and real-time weather (winds aloft, dropsonde data if available).
  2. Understand Ballistics: K-factors and rates of fall (RoF) vary by parachute type, load weight, and configuration. Use published data or aircraft databases accurately.
  3. DZ Coordination: Work closely with Drop Zone Controllers (typically Combat Controllers) and ensure the DZ meets AFI 13-217 criteria.
  4. Training: Regular practice with the MB-4, forms, and mission planning tools is essential for proficiency.
  5. Safety: Accurate CARP computation directly impacts mission success and safety. Off-DZ drops, malfunctions, or injuries trigger aerial delivery review processes.

Stay Current

Airdrop procedures evolve with technology (e.g., improved mission computers, guided airdrops). Always consult the latest editions of:

  • AFMAN 11-231
  • DAFMAN 13-217
  • Your MAJCOM and aircraft-specific instructions (e.g., AFI 11-2C-130 series)

For questions on form usage or computations, refer to your unit standards, navigators/CSOs, or the Air Force publications library.

Official Download Link (AF Form 4013):
https://static.e-publishing.af.mil/production/1/af_a3/form/af4013/af4013.pdf

This article is for informational purposes and does not replace official Air Force guidance. Aircrew must comply with current directives, technical orders, and command policies.

Keywords: AF Form 4013, Modified CARP Solution, Computed Air Release Point, USAF airdrop procedures, AFMAN 11-231, C-130 CARP, C-17 airdrop, drop zone operations.