Madrid - The captain of the MD-82 passenger plane that crashed in Madrid expected the airline Spanair to switch it after discovering a technical problem just before take-off, the Spanish daily El Pais said Monday.

Captain Antonio Garcia Luna, who was killed in the August 20 accident with 153 other people, asked an airport company employee to arrange for two buses to take the passengers to a new aircraft, the daily quoted the employee in question as telling police.

Garcia Luna had been about to take off when he noticed that a gauge measuring external temperature was not in order. He took the plane back to the hangar and asked technicians to inspect it.

The Spanair headquarters in Palma de Majorca said another aircraft was available if the technicians deemed a switch necessary, El Pais quoted judicial sources as saying.

Garcia Luna asked for two buses, which were driven to the MD-82.

The technicians, however, gave the plane the green light and it took off, crashing off the runway immediately afterwards. The causes of the accident remain unclear.

Spanair earlier denied a statement by Infrastructure Minister Magdalena Alvarez who said the carrier had intended to change the plane. Spanair said it was a standard procedure to check whether standby planes were available.

Spanair flights suffered at least 12 delays of up to 11 hours on Sunday. The accident was making the airline delay flights over minor concerns, passengers quoted Spanair employees as saying. The carrier quoted operational and technical reasons for the delays.

Spanair employees meanwhile wrote an open letter to Prime Minister Jose Luis Rodriguez Zapatero, asking him to make a "public gesture" to prevent an "unfair lynching" of the company after Alvarez' comments. The letter was published by the daily ABC.

Thirteen of the 18 survivors of the crash remain at hospital.