ACN/PCN Calculations Flashcards

Questions and Answers

Define PCN (Pavement Classification Number)?

Capability of a pavement to support an aircraft.

Define ACN (Aircraft Classification Number)?

Describes relative damage to pavement by aircraft and is based on aircraft weight and configuration, pavement type, and subgrade type.

What are all AF PCNs based on?

Full weight C-17 at 50,000 passes.

What are the origins of the ACN/PCN system?

1977-ICAO commissioned study looking at standards for reporting pavement strengths; 1983 - ICAO released ACN/PCN system; 1985 - AF began reporting PCNs for airfields. Signup and view all the answers

How is an ACN determined for a particular aircraft?

Back calculate the single wheel load which reproduces the stress/strain levels within pavement as the original landing gear; ACN = 2x derived single wheel load (in thousands of kg). Signup and view all the answers

How do you read an ACN (##/X/X)?

ACN -> Pavement type -> Subgrade strength. Signup and view all the answers

How do you read a PCN (##/X/X/X/X)?

PCN -> Pavement type -> Subgrade strength -> Tire pressure -> Type of evaluation. Signup and view all the answers

What are two options for determining the PCN of an airfield?

Using aircraft (XX/X/X/X/U) and technical evaluation (XX/X/X/X/T). Signup and view all the answers

What is the process for using aircraft in PCN determination?

Select largest ACN value of normal traffic aircraft permitted to use pavement and report as the PCN. Signup and view all the answers

How is technical evaluation used for PCN determination?

Determine the allowable load rating for aircraft AGL on the pavement and assign ACN of aircraft as PCN (preferred method). Signup and view all the answers

What are the limitations of the ACN/PCN system for determining aircraft/airfield capability?

Not all PCNs are based on C-17 at 50,000 passes; must know source of PCN, aircraft and pass levels used to compute it. Signup and view all the answers

Study Notes

Pavement Classification and Aircraft Classification

PCN (Pavement Classification Number): Measures a pavement's ability to support aircraft weight.
ACN (Aircraft Classification Number): Rates relative pavement damage caused by aircraft, factoring in aircraft weight, configuration, pavement type, and subgrade characteristics.

Development of ACN/PCN System

AF PCNs are originated from the full weight of a C-17 aircraft over 50,000 passes.
The ACN/PCN system was initiated by ICAO in 1977, resulting in a reporting standard released in 1983.
The U.S. Air Force started documenting PCNs in 1985 for airfields.

ACN Calculation Methodology

To determine an ACN, reverse compute the single wheel load that reflects original pavement stress/strain, with the equation ACN = 2 x derived single wheel load (in thousands of kg).

ACN and PCN Reading Formats

ACN Format: Presented as ##/X/X, where the first part is the ACN, the second indicates pavement type, and the last designates subgrade strength.
PCN Format: Shown as ##/X/X/X/X, including pavement type, subgrade strength, tire pressure, and evaluation type.

Methods for PCN Determination

Two distinct methods for determining PCN:
- Using Aircraft: Report the highest ACN from aircraft permitted on the pavement. This method lacks a standardized approach for defining "normal traffic."
- Technical Evaluation: Preferred method where the allowable load for Aircraft Ground Loading (AGL) is determined, assigning the allowable ACN as the PCN.

Limitations of ACN/PCN System

Not all PCNs derive from the benchmark of a C-17 at 50,000 passes; thus, understanding the source of a PCN is critical.
Knowledge of aircraft types and the number of passes utilized for calculating PCN is essential in determining airfield capabilities.

Description

Test your knowledge on ACN (Aircraft Classification Number) and PCN (Pavement Classification Number) with these flashcards. This quiz covers definitions and essential concepts related to aircraft and pavement capabilities. Perfect for aviation students and professionals.