Defective Steel in a New Aircraft

Airplane manufacturer Piper Aircraft Inc. issued a Mandatory Ser- vice Bulletin grounding 76 new aircraft manufactured during the first five months of 2004. Thirty-nine of the airplanes were in cus- tomers hands, and the rest were at dealers or at the Piper factory. The bulletin was issued after a production-line worker noted a bent seatbelt bracket in a new airplane. The defective bracket had been fabricated of high-strength steel that should have been very diffi- cult to bend. Investigation revealed that the steel was insufficiently strong. Piper traced the steel to a particular order and determined that a large number of other aircraft parts requiring the use of high- strength steel were manufactured from the same batch of steel. This signaled a flight-safety issue resulting in the grounding order and meant that Piper must locate, remove, and replace all the affected parts in all the airplanes.

Grounding a fleet of airplanes is a costly move. Piper had to absorb the cost of repairs, many of which were very difficult and, therefore, expensive. In addition, with half the airplanes scattered all over the globe, the manufacturer endured significant travel costs just getting to the planes. On the other hand, owners of the air- planes had to bear the cost of lost productive flight time while their planes remained grounded. The extent of damage to Pipers reputa- tion, along with customer loyalty and satisfaction, is unknown but could pose a blow to the companys future bottom lineall from a single order of high-strength steel.

It would be in the interest of all parties to find and eliminate the root cause of the problem. This information was known at the start of the investigation:

Piper purchased this batch of high-strength steel from its sup- plier, Wilco Inc. of Wichita, Kansas.

Wilco sent the raw (untreated) sheet steel to Certified Steel Treating, a Los Angeles company, to be normalized in a pro- cess that heats the steel to specified temperatures and then cools it at a controlled rate to increase its strength.

Then, as required for all normalized steel, it was sent to an inde- pendent lab for testing.

The steel and its certifying paperwork (which was all in order) subsequently went to Piper in Florida where it was used in the manufacture of critical aircraft parts.

Discussion Questions

Using the information available here, apply the seven steps of the Practical Problem-Solving Process.

1. Describe the initial problem perception.

2. Clarify the problem and set an improvement objective.

3. Determine the most likely point of cause (POC).

4. Suggest a root cause.

5. Develop a plausible countermeasure.