When Belgium's military decided to spend €31m (£26m) updating its fleet of 44 Pandur armoured vehicles, the main aim was to improve safety.
However, by improving the Pandur they reduced the size of the interior so that the maximum height of a driver or gunner is now below 1.70m (5ft 7in).
Belgians are known for being among the tallest in the world, so the news has been greeted with dismay.
The army insists armoured vehicle crews have always had limits on their height.
The revelations on height restrictions emerged in a report by public broadcaster VRT, but were not contested by the military. That would exclude the majority of Belgian soldiers.
The Pandur fleet was bought from an Austrian firm in 1996 but, according to VRT, had to be changed for use in foreign operations including in Mali in 2021.
The armoured vehicles did not have sufficient protection against roadside bombs and needed a second, raised floor as well as air conditioning for hot countries.
'Fiasco and waste of money'
They had originally been designed to move troops but had then been used as reconnaissance vehicles, officials explained. According to the Belgian Defence website, the Pandur is suitable for difficult terrain and weighs 13 tonnes.
The upgrade caused a "very serious nuisance", VRT reports, creating problems with the brake pedals and steering. "The raised floor makes getting in and out very difficult," an assessment was quoted as saying.
When it emerged that the upgrade meant only Belgians below average height could drive the APC, politicians condemned it as a "fiasco" and a waste of money.
Green MEP Wouter De Vriendt said the vehicles had been rendered useless for the role they had been given while a colleague talked of money being "thrown out of the windows".
'You've always had height restrictions'
Reacting to the outcry, the military admitted that the modified Pandurs were not immediately usable but had only gone through an initial upgrade.
"It won't be ready until it's had the entire modification," Adm Yves Dupont told broadcaster RTBF. "As far as ergonomics are concerned, the findings were known."
As for limiting the height of crew within the APC he maintained that "in this type of vehicle, you've always had height restrictions" and 1.70m was an average not uncommon with armoured vehicles.
The defence minister's chief of staff, Maj Gen Peter Devogelaere, pointed out that F-16 fighter jet pilots were restricted to a certain height too. The maximum for an F-16 pilot is put at 1.95m and the minimum is 1.62m.
The defence ministry was quoted as saying that so far only €1.7m had been paid out for the upgrade.