Madrid - The Spanair passenger plane which crashed in Madrid last week lacked engine power to take off, Spanish press reports said Tuesday.

A stewardess who was the only crew member to survive, and most other witnesses reported that the plane was struggling to rise in the air, according to the daily El Pais.

One of the plane's two engines had the reverse system, which helps aircraft to slow down when landing, turned on. It was not known whether the pilot had activated it when noticing that the plane was unable to take off.

Wednesday's crash killed 154 people. A six-year-old boy who lost his 16-year-old sister in the accident became the first survivor to leave hospital on Monday.

Sixteen people remain at hospital, eight of them in serious condition. (dpa)