"In a plane, the computer must work or the plane can't fly. At Northrop,
the computer must work or the planes can't get built. (Vasilash, Gary S.
"Manufacturing by Wire." Production June 1990, p. 85.)
Northrop Aircraft Division (NAD) production plant in Hawthorne, CA uses a
computer to run its facilities. NAD assembles the F/A-18 Hornet fighter, an
aircraft used by the U.S. Navy and Marine Corps in this plant. The assembly
line combines the elements that make up the center and aft fuselage sections,
the twin vertical stabilizers, and the associated subsystems.
In 1978 Northrop began building the F/A-18 in its plants in Hawthorne and
nearby El Segundo. Between 1978 and the first few months of 1989 it produced
842 assemblies, or "shipsets," as they are known in the aircraft field. Each
shipset requires 16,295 sheets of paper - schedules, part lists, tooling,
inspections, nonconformance data. During the Paper Age (i.e., 1978-89) this
plant produced more than 13.45 million sheets of paper were used. (Vasilash,
Gary S. "Manufacturing by Wire." Production June 1990, pp. 85-89.)
Integrated Planning and Control for Assembly
In February 1989, NAD converted its F/A-18 final assembly to an entirely
paperless manufacturing shop-floor control system. NAD developed the
computerized system that manages the production line, Integrated Planning and
Control for Assembly (IMPCA), in-house. The IMPCA system was critical to the
production process and was on a fault-tolerant Tandem computer system. (Best
Manufacturing Practices (BMP) Review Team. Best Manufacturing Practices,
Report of Survey Conducted at NAD, Hawthorne, CA. Washington, DC: Office of
the Assistant Secretary of the Navy (Shipbuilding and Logistics), March 1989,
By converting to the IMPCA system, NAD eliminated 400,000 pieces of paper
at 104 stations in 14 cost centers on the line. The projected cost savings
through the F/A-18 contract was $20 million. The IMPCA system
work planning, instruction, and dispatching
work performance monitoring and evaluation
maintenance of electronic records
The conversion plan was critical to the success of the IMPCA program. Four
key aspects of the plan were:
informing and educating affected employees
developing prototypes and doing simulations for selected centers
installing and transferring to IMPCA without disrupting the line and the
validating the new system as functionally equivalent
to the previous paper-driven one
During the conversion to the automated system, 15 shipsets were produced
using both the paper-driven and the electronic methods. The first five of the
15 shipsets were used to introduce the staff to the system and were not a part
of the validation process. The last ten were used by the Air Force Plant
Representative Office for in-depth validation of the new system. When minor
discrepancies were found during validation, they were equally likely to be in
the paper-driven system or the new one.
Other key aspects of NAD's approach to the conversion plan that contributed
to success are:
simulation of three production work centers to better explain shop-floor
approval of changes only by a change-control team made up of users, data-
processing staff, manufacturing-initiatives-process staff, and project
password and electronic-stamp security built in the
system that limits document ownership to only one user at a given
NAD recognized that perhaps the biggest obstacle was employee acceptance.
Fear of the system was overcome through briefings and training programs that
began two years before the conversion. The system included user-developed
guide screens that dealt in specific terms and methods familiar to the users.
During the final stages of the education process, experienced users in each
center conducted the hands-on training for their fellow employees.
At the center of the IMPCA system is an on-line transaction processing
fault- tolerant computer. The system needs to be up for production all the
time except when it is under maintenance for 20 hours per week. The IMPCA
system enables in real-time to:
determine quality trending
discover backlogs or bottlenecks
schedule quality assurance
make engineering changes
The system has improved the overall quality of the production process by
providing real-time access to data. Approved users can access data at any
terminal. The system's monitoring capabilities assure that tasks are done
properly. New data gathered is available promptly to adjust time standards.
Up-to-the minute status information, which indicates the progress of jobs, is
In the post-Paper Age, each plane is fully documented by 36 (4 in. by 6
in.) microfiche cards. Gary L. Lampkins, Manager, F/A-18 Assembly Operations
IMPCA claims that it is the only paperless aircraft factory in the world.
(Vasilash, Gary S. "Manufacturing by Wire." Production June 1990, pp.
With each succeeding shipset produced in a paperless mode, NAD has become
more confident about the IMPCA system and paperless manufacturing. Migration
plans are being generated for other NAD programs, such as the 747 and B-2.