The Event

Date: 10 December 1998.

Location: Amsterdam Schiphol Airport, The Netherlands.

Summary: On 10 December 1998, an incident occurred at Schiphol (Amsterdam) Airport in which a Delta Air Lines Boeing 767 aborted its take-off roll when the pilots observed a towed Boeing 747 crossing the runway in front of them. At the time of the incident, low visibility procedures were in force. After unclear radio transmissions with the tow truck driver, an assistant controller had passed her interpretation of the tow’s position to the trainee controller responsible for the runway. The assistant controller did not have a screen that could show ground-radar pictures. The trainee controller did, and took the position of the tow at the edge of the runway to mean that the crossing had been completed. Buttons on a newly-added panel in the tower for controlling lighted stop-bars at runway intersections proved ambiguous, but at the time all looked in order, and he cleared the other jet for take-off. Meanwhile, the coach of the trainee controller was performing supervisor duties in the tower.

The Non-Judicial Investigations

Carried out by:

• Incident Investigation Department of ATC The Netherlands (LVNL), and a report was published on 4 March 1999.
• Dutch Transport Safety Board (DTSB), who published a report in January 2001.

The Findings:

Both investigations arrived at similar conclusions.

Contributing factors identified in the LVNL report included the following items:

• There was uncertainty about the operation of buttons on a newly added panel in the Tower for the control of stop bars at the runway intersection where the tow was crossing. In addition, the labelling of these buttons was found to be ambiguous.
• The working position of the Assistant Controller was not equipped with a screen on which a ground radar picture could be selected.
• The Coach of the Trainee Controller simultaneously had to perform Supervisor duties in the Tower.

LVNL issued 23 recommendations, all of them aimed at rectifying systemic arrangements in, for example, design, layout, staffing, coaching, communication and handovers.

The DTSB report identified the following "causal factors":

• Low visibility weather conditions which prevented Air Traffic control to visually identify vehicles on the ground;
• Inadequate information during the radio communications between the tow-combination and Tower;
• Misinterpretation of position and movement of the tow;
• Take-off clearance without positive confirmation that the runway was unobstructed;
• Insufficient teamwork and supervision.

The DTSB made 9 recommendations (quite similar to LVNL) that were all aimed at correcting identified systemic deficiencies in the organisations of ATC The Netherlands and the Schiphol Airport Authority.

The Criminal Prosecution

Persons Prosecuted:

• The ATC Coach/Supervisor
• The Air Traffic Controller - trainee
• The assistant Air Traffic Controller

The Charge(s): Two years after the incident, the aviation prosecutor decided to formally charge the coach/supervisor, the trainee and the assistant controller with "the provision of air traffic control in a dangerous manner, or in a manner that could be dangerous, to persons or properties." (Dutch law contains such provisions).

The First Hearing: A first criminal court case was held a year and a half after the incident in August 2001. The judge ruled that the assistant controller was not guilty, but that both the trainee and the coach/supervisor were. They were sentenced to a fine of about 450 US dollars or 20 days in jail.

Appeal Lodged: The trainee and the coach/supervisor decided to appeal the decision, and the prosecutor in turn appealed against the assistant controller’s acquittal. More than a year later - in September 2002, the case was brought before a higher court, composed of three judges. As part of the proceedings, the judges, prosecutor and their legal team were shown the airport’s tower (the “scene of the crime”), to get a first-hand look at the place where safety-critical work occurred.

The Sentence after the appeal: The court found all three accused guilty as charged but did not impose any sentence. This determination treated the case as an "infringement of the law" rather than an "offence against the law". In Dutch law, an infringement means “guilt in the sense that blame is supposed to be present and does not need to be proven”. The only admissible defence against this determination is being devoid of all blame which could only succeed if a controller was off-duty and therefore not in the tower. The determination also had the effect of removing any option of appeal because there has been no conviction of an offence and no punishment.

The court recognised that the facilities in the control tower for the prevention of such incidents were "less than optimal", as evidenced by the improvements implemented after the incident.

In its judgement the court included that the prosecution of the three controllers for this "infringement", that occurred in the course of their professional duties, had deeply affected their lives.

The court took into consideration the indication by the prosecutor that this case for her was somewhat of a legal "test case".

In its judgement the court included that none of the defendants had a criminal record and that there were no indications that in exercising their responsible functions they had ever failed before.

Related Facts

• Over the years that the legal proceedings went on, the number of incident reports submitted by controllers dropped by 50%.
• This incident and its legal aftermath did help the development of a new, local solution which included a so-called “judge of instruction” in the Netherlands. The judge of instruction, supported by an industry panel, should function as an intermediary, who gives a prosecutor permission to go ahead with a case or not.

Related Articles

• Runway Incursion
• B763 / B744, Amsterdam Netherlands, 1998 (RI HF) A Summary of The Dutch Transport Safety Board Incident Report.
• B742 / B741, Los Rodeos Tenerife, 1977 (RI AGC WX)
• Human Error in Aviation and Legal Process
• Just Culture