A pilot who caused panic in Frankfurt after threatening to crash his stolen aircraft into a skyscraper was apparently seeking to commemorate a dead astronaut.

I want to make my great idol - Judith Resnik - famous through this

I want to make my great idol - Judith Resnik - famous through this

Pilot

Franz Stephan Strambach, a 31-year-old a psychology student, was arrested after more than two hours in the sky, during which time he said he would fly into the tower of the European Central Bank.

A state court judge in Frankfurt ordered that he be transferred to a mental institution pending a decision by authorities on whether he is fit to be charged.

"This was not a terrorist attack, but the act of an apparently disturbed person," a spokesman for German air traffic control, said at a news conference on Monday.

Shortly before his descent, Mr Strambach told a TV station that he was trying to draw attention to Judith Resnik, one of the astronauts killed when the US space shuttle Challenger exploded in 1986.

"She deserves more attention - she was the first female Jewish astronaut and that is probably why she has never been taken much notice of," he told n-tv, which had established contact with him through the control tower.

: Frankfurt hijack Pictures of air drama

According to reports, he came down after being allowed a telephone call to Ms Resnik's family in the United States, during which he discussed a tribute page to Ms Resnik he had set up on a website.

Close call

Thousands of people were evacuated from tall buildings or ordered by police to take shelter underground as the plane swooped erratically round the city on Sunday.

The plane - which had been stolen at gunpoint from an airport in Hessen - was followed by a police helicopter and German fighter jets.

At one point, it came within about 30 metres of the ECB headquarters.

As a precaution, German police evacuated the whole financial district and the railway station. The city's airport - one of the busiest in Europe - was also closed.

Bridges across the River Main were sealed off, as were several main roads.

Security questions

Onlookers said that the incident brought back frightening memories of the 11 September 2001 attacks in New York and Washington, in which more than 3,000 people died.

BBC correspondent Katya Adler said the incident would raise serious questions over the state of security in Germany's cities, which was stepped up following the 11 September attacks.

She adds that Frankfurt had been considered particularly at risk because of its many tall buildings.

There have been similar incidents in the past year involving light aircraft.

In January last year a 15-year-old American boy, Charles Bishop, flew a stolen single-engine Cessna into the 20th floor of a skyscraper in Tampa, Florida, killing himself and slightly damaging the building.

And in April last year a Swiss-based man thought to have financial difficulties crashed a small Piper aircraft into the famous Pirelli skyscraper in Milan, Italy, killing himself and two women.