Customer Grants "Temporary Approval" and Production Lines Go Full Throttle? — Decoding Conditions of PPAP Temporary Approval and the Five-Step Method for Closing the Loop

A certain automotive parts company received a new project. The status column of the PSW read "Temporary Approval (Interim Approval)," with a small line below: "Submit an improvement plan within 90 days and re-submit the initial process study." The project manager, seeing the word "approved," laid out a three-shift schedule and shipped the first batch of 2,000 pieces within three days. On the 40th day, the customer conducted a process audit and casually asked, "How is the additional stringent inspection during the temporary approval period going?" The workshop director couldn't answer, and the inspection records only contained full inspection data for the first two weeks. The customer immediately upgraded the status to controlled shipment (CS2), delaying the delivery schedule by two weeks. The company had to bear the additional costs of full inspection, re-packaging, and on-site audit.

The issue is not that the company doesn't value the customer, but that everyone along the chain—project manager, planner, workshop, and inspection—received only one signal: "approved." As for what this approval entails, what conditions are attached, and when these conditions expire, none of these were translated into actionable steps. The PSW lay in the project folder, the conditions scattered in the customer's emails and WeChat chat records, and the production line continued as usual, with the control plan following the normal sampling inspection. This is not an isolated incident but the most common type of失控 in PPAP approval status management.

1. What Exactly is Temporary Approval: Five States, Three Levels of "Value"

The result of a PPAP submission is not a simple pass or fail, but a set of states with entirely different meanings. Aligning their commercial implications is the starting point for all subsequent actions.

The most easily misinterpreted rows in this table are the second and third. Temporary approval is not a "discounted approval," but a "conditional permit." The conditions are the main focus, and the permit is granted in exchange for meeting these conditions. Customers typically grant temporary approval for one of four reasons:

• Insufficient process capability: Ppk falls between 1.0 and 1.33. Safety-critical or regulatory parts may not be accepted at all, while general characteristics are given an improvement window.
• Individual characteristics out of tolerance but do not affect function: The deviation is clear and the impact is controllable. The customer uses "acceptance conditions" to lock in the risk.
• Long verification cycle tests not yet completed: Such as durability, aging, and salt spray tests. The report hasn't come out yet, so a temporary approval is used to maintain project milestones.
• Missing documentation: Material certificates, sub-supplier PPAP, laboratory qualifications, etc., are incomplete, but the actual risk is minimal.

These four sources determine the "value" of the temporary approval. Clearly distinguishing these sources is essential to determine how many resources should be allocated and to what level of detail the temporary approval should be monitored. Conversely, treating a temporary approval as a regular approval is equivalent to voluntarily giving up the "conditional buffer" provided by the customer, turning a controllable risk into an uncontrollable delivery incident.

2. Condition Decoding: Translating the Customer's One Sentence into Four Rows of Records

Eighty percent of issues with temporary approval stem from "conditions not being decoded." The customer's approval letter or PSW notes often contain just one sentence, such as "Accept the deviation, submit an improvement plan within 90 days, and strengthen inspections during this period." This sentence actually contains four elements, and missing any one of them can lead to misalignment:

For example, "Submit an improvement plan within 90 days." If calculated in natural days, three months could be 89 days or, due to the Spring Festival holiday, only 60 working days. If the customer requires an "improvement plan" or "improvement verification results," the deliverables are entirely different. The result of decoding is not a meeting minutes but a row in the "Temporary Approval Record Form": part number, deviated characteristic, acceptance conditions, responsible department, expiration date, period control, and current status. The principle of designing the record form fields is: anyone not involved in this submission should be able to determine "whether they can ship now, what to ship with, and what is still needed before the deadline" by looking at this row.

When decoding, there are three essential questions that many companies fail to ask: First, clarify the scope of the approval—does it cover all batches shipped to the customer or only specific batches and locations? Second, clarify the conditions for lifting the strengthened measures—do they automatically expire or require written confirmation from the customer? Third, clarify who will receive the rectification evidence—is it the customer's SQE or the purchasing department, and how long will it take to get feedback? Answering these questions makes the subsequent reverse planning meaningful.

3. Five-Step Method for Closing the Loop on Temporary Approval

Step 1: Condition Decoding, Create the "Temporary Approval Record Form"

Using the customer's approval letter (or PSW notes, emails), decode each of the four elements and register them in the record form, marking the "source of deviation"—capability, out-of-tolerance, testing, or documentation. The record form should be stored in a shared location, not in an individual's local folder. The acceptance standard for this step is simple: any person should be able to state within five minutes how many temporary approvals are currently in place and when each expires.

Step 2: Translate Conditions into Internal Control Measures

During the temporary approval period, there must be visible differences between the company's operations and normal mass production. This is not just a gesture for the customer but a necessary action to lock the risk within the factory. It is recommended to use a comparison table to solidify these differences:

The value of the comparison table lies in its "inspectability." When an auditor or customer SQE visits the site, they can judge whether the conditions of the temporary approval are being implemented by looking at the proportion of inspection records, the identification, and the shipment approval forms—rather than just hearing "we take it very seriously."

Step 3: Reverse Planning and Milestone Alerts

Break down the rectification deadline into milestones and assign them to individuals. For a 90-day rectification period, a general framework is: T-90—develop an improvement plan and assign responsibility, T-60—complete the first batch of post-improvement sampling, T-45—complete capability re-measurement, T-30—submit the initial draft of the improvement verification report, T-14—customer confirmation, T-3—complete all evidence and internal pre-review. Each milestone is marked with a red, yellow, or green light in the record form, with T-30 being the red line: if the improvement evidence is not in place by this point, a contingency plan must be initiated—either by requesting a reduced verification scope from the customer or by preparing an extension application in advance, rather than passively explaining on the last day.

Step 4: Close Rectification with Data, Form the Re-submission Package

The closure of a temporary approval does not rely on the conclusion "we have fixed it" but on a set of evidence that can be directly reviewed by the customer. For capability issues, this typically requires: the updated control plan and work instructions, the initial process study after improvement (sufficient data from continuous batches), synchronized updates to the PFMEA and CP, and records verifying the effectiveness of the corrective actions. For documentation issues, it involves completing the missing material certificates, sub-supplier PPAP, test reports, etc. Before re-submission, conduct an internal self-assessment based on "what the customer might criticize": are the samples taken from stable post-improvement production, is the sampling continuous, are the measuring instruments within their validity period, and is the data comparable to pre-improvement data? A common technical reason for rejection is: only 3 batches of post-improvement sampling, when the customer requires 25 sets or 100 consecutive pieces, resulting in insufficient evidence and a wasted 30-day window.

If the improvement cannot be completed within the deadline, the correct action is to apply for an extension in advance, not to remain silent until the deadline. The extension application should include three points: the extent of completion (with evidence), the technical reasons for the remaining gaps (whether it is due to equipment modification cycles, mold revisions, or supplier rectification), and the new committed deadline and interim strengthened measures. Customers are far more likely to accept an "honest and planned" extension application than an explanation after the deadline. Another scenario is when the customer directly specifies controlled shipment: in this case, the temporary approval and CS1/CS2 requirements are executed concurrently. The company must meet both the rectification requirements of the IA and the additional inspection, identification, and shipment approval requirements of controlled shipment, adhering to the stricter set of requirements and not just one of them.

Step 5: Expiration Review and Status Closure

The expiration date is the "gate" for temporary approval management. On this day, there are only three possible outcomes: closure and transition to approval, active application for extension, or downgrade or transition to controlled shipment. All three outcomes are acceptable, but the fourth—silent delay—is not. The consequence of silent delay is not that the customer doesn't notice, but that they will discover it during the next audit or annual performance review. At that point, the nature of the issue shifts from a "capability problem" to an "integrity problem," with entirely different levels of punishment.

Reviewing the case of the stamping parts company: the deviated characteristic was the assembly dimension with a CPK of 1.12. The customer granted a 90-day temporary approval, with the condition of full inspection and a report for each batch. The company indeed conducted full inspections for the first two weeks, but due to order pressure, reverted to sampling in the third week and stopped attaching reports by the fifth week. On the 40th day, the customer's audit found that the conditions had been suspended, upgrading the status to controlled shipment, incurring additional costs for third-party on-site inspections, and placing the supplier on the key supervision list for the next year. The rectification was only completed by the 75th day. If the company had strictly followed the five-step method, it would have only borne the cost of full inspections for 90 days, rather than the long-term supervision and loss of trust that followed.

4. Seven Common Pitfalls

1. Misinterpreting "Temporary Approval" as "Approval". This is the root of all problems. Seeing the word "approved" and going full throttle is equivalent to voluntarily giving up the risk buffer provided by the customer.
2. Three-Minute Enthusiasm for Strengthened Measures. Full inspections for the first two weeks, followed by a return to sampling, is the most typical decay curve during the temporary approval period. Strengthened measures must be written into the control plan and inspection guidelines, enforced by policy, not by individual initiative.
3. Strict Only on Sample Pieces, Lenient on Shipment Batches. The conditions of the customer's temporary approval apply to "products delivered to the customer," not just "samples sent to the customer." The inspection standards for both must be aligned according to the conditions.
4. Conditions Scattered in Emails and Chat Records. Without a record form, no responsible person, and no expiration reminders, the chain breaks when personnel changes. The record form is the only source of truth.
5. Control Plan Not Updated to Reflect Temporary Approval Conditions. The CP still follows the normal sampling frequency, and the production line operates according to the CP, appearing compliant but actually out of sync with customer requirements. Once the temporary approval takes effect, the immediate update of the CP is a hard requirement.
6. Treating "Approved for Shipment" as Formal Approval. This status means the customer reserves the right to reject. Shipped goods may be recalled and lead to claims. The company must have precise batch traceability and rapid recall capabilities.
7. Not Feeding Back After Closure. After rectification and transitioning to approval, the company archives the experience. The correct approach is to document the root cause of the deviation and the corrective actions in the PFMEA and control plan, and update design specifications for similar parts if necessary, turning a temporary approval into a capability enhancement rather than a lucky pass.

5. One Sentence Summary

Temporary approval is not approval; it is a conditional permit granted by the customer using "conditions + deadline" to control risk. Decoding each condition, implementing it on-site, and closing the loop by the deadline is the true way to earn mass production qualification.

Temporary approval is a conditional permit, and it must be closed by the deadline.

Knowledge code: 8.3.3

Version: v20261003

Author: QTank QTank is dedicated to providing systematic professional knowledge, methodologies, and practical tools to quality management practitioners, helping companies continuously improve their quality capabilities.