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Aviation glossary

Line number

Also: L/N, production line number, ln

Registration and rules

Number showing the order in which an aircraft left its type's assembly line; a convention used mainly by Boeing alongside the serial number.

What it is

At Boeing, serial numbers are usually allocated in blocks when a customer places an order, so they do not reflect the build sequence. The line number does: the first 747 assembled is line number 1, and every aircraft that followed took the next number, whatever its customer or variant, up to 1,574 for the last one built. Two aircraft with widely separated serials may therefore have come off the line one after the other.

The line number helps place an aircraft within its type's production run and is often used to define which aircraft a modification applies to. A sequence does not always cover a whole model: Boeing started a fresh numbering series with the 737 Next Generation, so a line number only makes sense alongside its type. At Airbus the serial number broadly follows the build order, so a separate line number is rarely quoted.

On Vuelopedia

Boeing 747 Boeing 737 Boeing

Related terms

MSNSerial number assigned by the manufacturer to each aircraft which, unlike the registration, stays with it unchanged for its entire life. Final assembly lineThe facility where the major sections of an aircraft, often built at other plants, are joined and its systems installed until it is ready to fly. DeliveryThe handover of a new aircraft from its manufacturer to the customer, an airline or a lessor, after acceptance checks and final payment. Boeing customer codeTwo-character code that Boeing assigned to each customer and added to the model designation, as in the 747-436 built for British Airways.
Whole glossary

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This page was last updated on October 9, 2026

APA

Vuelopedia. (2026, October 9). Line number. Retrieved October 16, 2026, from https://vuelopedia.org/en/glossary/line-number

MLA

“Line number.” Vuelopedia, Fundación Poderia, 9 Oct. 2026, vuelopedia.org/en/glossary/line-number. Accessed 16 Oct. 2026.

Chicago

Vuelopedia. “Line number.” Fundación Poderia. Last modified October 9, 2026. https://vuelopedia.org/en/glossary/line-number.

Harvard

Vuelopedia (2026) Line number. Available at: https://vuelopedia.org/en/glossary/line-number (Accessed: 16 October 2026).

BibTeX

@misc{vuelopedia_en_glossary_line_number,
  author       = {{Vuelopedia}},
  title        = {{Line number}},
  publisher    = {Fundación Poderia},
  year         = {2026},
  date         = {2026-10-09},
  url          = {https://vuelopedia.org/en/glossary/line-number},
  howpublished = {\url{https://vuelopedia.org/en/glossary/line-number}},
  urldate      = {2026-10-16},
  note         = {Accessed 2026-10-16}
}

Wikipedia

{{cite web |url=https://vuelopedia.org/en/glossary/line-number |title=Line number |website=Vuelopedia |publisher=Fundación Poderia |date=2026-10-09 |access-date=2026-10-16 |language=en}}

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