Syria conflict: Half of German Tornado jets 'not airworthy'
Only 29 of Germany's 66 Tornado jets are airworthy, a defence ministry report has revealed.
It comes two days before German MPs are expected to vote in favour of military action against Islamic State (IS) militants in Syria.
Defence Minister Ursula von der Leyen has stressed that only six of the operational Tornado jets would be needed for the proposed mission.
A vote on the UK's involvement takes place in parliament on Wednesday.
Germany decided to join the fight against IS after an appeal by French President Francois Hollande in the wake of the 13 November Paris attacks.
But the readiness of Germany's armed forces has long been the subject of criticism.
'Long and dangerous'
"The state of our flying systems remains unsatisfactory," the German army's chief of staff General Volker Wieker was quoted as saying on Wednesday.
The defence ministry report, obtained by German media, blamed the problem on the "lack of availability of various spare parts".
Six Tornado reconnaissance aircraft, a naval frigate and a 1,200-strong force will be sent to Syria under the proposals backed by the German cabinet on Tuesday.
The Bundestag is set to start debating the plans on Wednesday, with a vote expected on Friday.
Speaking to German TV channel ARD (in German) on Wednesday, Defence Minister von der Leyen said: "Thirty Tornados are ready for action, and we need six of them. That gives us a wide margin."
She stressed that any military operation against IS in Syria would be "long and dangerous".
The latest defence ministry report showed Germany's air force capability further depleted from the year before, when 38 of 89 Tornado fighters were operational.
Critics have accused the Christian Democratic Union (CDU) defence minister of neglecting important areas of military investment such as armour development.
Last year she was forced to admit Germany's military equipment was in such poor repair that the country could not meet its Nato obligations.
Technical problems grounded German military aircraft delivering weapons to Kurds fighting IS in northern Iraq and medical aid to West Africa during the Ebola outbreak.
A YouGov opinion poll published on Tuesday showed 71% of people in Germany believed involvement in a mission against IS in Syria would raise the threat of attack in the country.
However, 45% of Germans questioned backed military involvement and 39% were opposed.
Until now, Germany's biggest foreign mission has been in Afghanistan, but that has gradually wound down to a force of just under 1,000.
Some 700 German soldiers are also part of the Nato-led K-For operation to stabilise Kosovo.