What Is First Article Inspection (FAI)

What Is FAI with TofuPilot

First article inspection (FAI) is a detailed verification of the first production unit to confirm that the manufacturing process can produce parts that meet all design specifications. It's required by aerospace (AS9102), automotive (PPAP), and medical device standards. This guide covers what FAI involves, when it's required, and how to track FAI results with TofuPilot.

What FAI Verifies

FAI checks every characteristic on the drawing and specification, not just the critical ones. It's a full accounting of:

FAI is not sampling. It's a complete inspection of one unit (or a set of units) against every requirement.

When FAI Is Required

FAI Documentation (AS9102)

AS9102 defines three standard FAI report forms:

Form 3 is the most labor-intensive. Every dimension on the drawing gets a balloon number, and the corresponding measured value goes in the FAI report.

Prerequisites

• Python 3.10+
• OpenHTF installed (pip install openhtf)
• TofuPilot Python SDK installed (pip install tofupilot)

Step 1: Define FAI Test Phases

The functional test portion of FAI runs the same test procedure as production, but you record every measurement, not just pass/fail.

import openhtf as htf
from openhtf.util import units


@htf.measures(
    htf.Measurement("output_voltage_V")
    .in_range(minimum=4.9, maximum=5.1)
    .with_units(units.VOLT),
    htf.Measurement("ripple_voltage_mV")
    .in_range(maximum=50)
    .with_units(units.MILLIVOLT),
    htf.Measurement("efficiency_percent")
    .in_range(minimum=90)
    .with_units(units.PERCENT),
    htf.Measurement("leakage_current_uA")
    .in_range(maximum=500)
    .with_units(units.MICROAMPERE),
)
def phase_fai_electrical(test):
    """FAI Form 2: All electrical characteristics."""
    test.measurements.output_voltage_V = 5.02
    test.measurements.ripple_voltage_mV = 18.3
    test.measurements.efficiency_percent = 93.7
    test.measurements.leakage_current_uA = 65.0


@htf.measures(
    htf.Measurement("firmware_version").equals("2.1.0"),
    htf.Measurement("boot_time_ms")
    .in_range(maximum=2000)
    .with_units(units.MILLISECOND),
    htf.Measurement("self_test").equals("PASS"),
)
def phase_fai_functional(test):
    """FAI Form 2: Functional characteristics."""
    test.measurements.firmware_version = "2.1.0"
    test.measurements.boot_time_ms = 1120
    test.measurements.self_test = "PASS"

Step 2: Log FAI Results to TofuPilot

The FAI test runs once on the first article. TofuPilot stores every measurement with its limit, unit, and result.

from tofupilot.openhtf import TofuPilot

test = htf.Test(
    phase_fai_electrical,
    phase_fai_functional,
)

with TofuPilot(test):
    test.execute(test_start=lambda: input("Scan first article serial: "))

Step 3: Generate the FAI Report

TofuPilot stores the complete test record for the first article. Open the unit's test history to get:

• All measurements with actual values against specification limits
• Pass/fail status for each characteristic
• Timestamps for audit trail
• Test reports exportable for AS9102 Form 2 documentation

This data feeds directly into the FAI report. Instead of transcribing measurements from a bench multimeter into a spreadsheet, the test data is already structured and auditable.

FAI vs Production Test

FAI proves the process is capable. Production test proves each unit is conforming. Both are necessary. TofuPilot tracks both using the same infrastructure.