For a company intent on maximum efficiency, the problem needed sorting out.
So Airbus, which employs 7,000 at Broughton making aircraft wings, (including for the A380, the world's largest commercial airliner which took its maiden flight last week) thrust it in the lap of Deeside college, currently training 400 of its apprentices.
Airbus's goal, in industry jargon, is lean manufacturing. That means eradicating waste.
"You can't look at people like bits of metal but what it came down to was, if we have 120 apprentices starting, why aren't 120 passing?" said Deeside principal David Jones.
"Airbus had ramped up expectations and told us our current standards weren't good enough. We took a big gulp and said these were issues we'd have to face together."
As apprentices were slipping through with inadequate basic skills, Deeside insisted they should all be screened after selection. "Some were reluctant but we told the company we wanted its support to make screening compulsory," said Mr Jones.
"That was a sticking point. It meant tackling senior management. The immediate reaction was, these people have GCSEs, have we messed up? Should we be getting rid of them? There was a culture we needed to break down."
Gary Griffiths, who manages the apprenticeship programme at Airbus, said:
"The general perception is that when you recruit at this level you would expect them to have the basic skills. Yet we've found that up to one in three may need extra help.
"My view is that if you look at any person with a grade C in maths they might have taken the intermediate paper and not done the level you expect.
They may have been only one mark away from a grade D.
"Screening has identified that even some of our craft apprentices and higher apprentices have deficiencies. A lot of the time dyslexia was going unnoticed."
Airbus now has psychometric tests to help its selection process. But screening, which has been running five years, makes a big difference "We've had an apprentice of the year who had full extra support throughout his time," said Mr Griffiths.
In Llanelli, Coleg Sir Gar screens apprentices taken on by the German motor components manufacturer Ina Bearings.
This is part of a strategy to raise technical standards and prevent jobs haemorrhaging to eastern Europe.
Coleg Sir Gar has had a 50-year relationship with Ina, which employs 200, but whose future in West Wales looked doubtful five years ago. "We were called in by the senior management. It was a rescue package," said Barry Liles, faculty manager for engineering and construction.
Like Deeside, Coleg Sir Gar had to combat a sense of stigma among those being screened. Ina Bearings' school-leavers now spend all their first year at college.
"Some came to us with grade A maths in GCSE but were still deficient in numerical skills," said Mr Liles. "I have watched this decline over the past 10 years."
Ina has turned the corner and its future in Wales seems secure.