An Aer Lingus passenger jet, on a scheduled flight to Dublin with over 100 people on board, was involved in a near miss with a light aircraft at Birmingham airport, according to a report into the incident released yesterday.
The report concludes that the incident happened when the Aer Lingus jet took off without full clearance to do so.
The "near ground collision" occurred on April 28th at 4 p.m. when the Aer Lingus jet began to take off on runway 33 without clearance, while a smaller plane on a routine training exercise was landing on another runway which crossed the path of runway 33, according to a report into the incident by the air accident investigation branch of the Civil Aviation Authority in the UK.
A major accident was averted by the quick reactions of the controller who realised the danger when he heard the noise from the Aer Lingus jet engines as it approached the Piper PA 38's landing path. He immediately issued instructions to the Aer Lingus jet to "hold position".
The instructor in the other aircraft was alerted to the impending danger from the Aer Lingus jet by the "tone" of the controller's voice issuing instructing to the jet to abort its take-off. The controller then instructed the lighter Piper aircraft to "turn left now". The instructor took over from the learner pilot and tried to stop the aircraft crossing the path of the jet.
Although the captain of the Aer Lingus jet saw the PA 38 by the time he aborted take-off, he was unable to stop the aircraft before the intersection of the two runways, with the result that the left wing of the Aer Lingus jet passed over the right wing of the light aircraft as it slowed down.
When the Aer Lingus jet eventually came to a halt, at hold K (in diagram), the captain asked the tower, "did we hit him?", to which the controller replied, "negative".
The report found that that incident occurred as a "result of an accumulation of factors".
Under a new procedure designed to improve safety during the critical seconds after take-off, the control tower instructs pilots to switch to another radio channel when they reach 2,000 feet. This instruction would normally be followed with a clearance for takeoff.
On this occasion the pilot assumed the clearance for take-off instruction had been given after the frequency change instruction, when in fact it had not.
Although the report found that the controller had "misinterpreted" the correct procedure for the departure instructions to the pilot, it also found that the Aer Lingus pilot's failure to read back the instruction "denied to the controller the opportunity to correct the error", and thereby avert the potential disaster earlier.
The report concludes that "the incident occurred because the (Aer Lingus) BAe 146 took off without a clearance".
However, failure to identify pitfalls in the frequency change procedures before take-off are also identified as contributing to the "near ground collision."
The report also concluded that more analysis could have been carried out on the safety of the frequency change procedure, which never anticipated "the potential for a pilot taking off without a clearance".