A Gulfstream GIV-SP of the Swedish Air Force with four crewmembers and four passengers on board was parked on the northern apron of Berlin-Tegel Airport (EDDT) on Jan. 12, 2007. An IFR flight plan from Tegel to Bremen, Germany, had been filed and was ready for the crew when they showed up at the airplane.
The crew completed normal preflight procedures and called for engine start. They simultaneously requested to use Runway 26R for the later takeoff. To help understand the situation that followed, know that there were two parking places involved, the northern and southern aprons. The two ramp areas are separated by dual east-west (8-26) runways. Of the two, 26R is the longer runway at 9,918 ft., while 26L is 7,966 ft. Both runways are 151 ft. wide.
In this incident, airplanes eventually are cleared from both parking areas to the line-up end of Runway 26R and 26L.
The terminal buildings for civil aviation are located to the south of the two runways. The airport tower is also located to the south of the runway. Military aircraft generally use the northern apron and from there Taxiway NE goes in an easterly direction. Initially parallel to the runway, it then turns to the southeast and eventually due south as it approaches the dual runways. From the southern apron, Taxiway SE goes in an easterly direction to Runway 26L and 26R.
The weather on that winter day was not a factor. Even though a light rain was falling, the cloud bases were basically few at 1,000 ft. with scattered to broken at 2,700 and 3,200 ft. Visibility was 10+ kt. The temperature was a crisp 45F and the dew point was 37C with an altimeter of 1014.
In command of the Gulfstream was a military-rated 54-year-old pilot, typed in the GIV-SP for over 12 years. He had more than 6,000 hr. experience in the airplane and in the previous 73 days had flown 73 hr. and performed 20 landings.
The 40-year-old copilot had been in the Swedish Air Force for four years. He held a military pilot license and had been typed in the GIV for over two years at the time of the incident. He had over 3,500 hr. in the airplane and had also flown 73 hr. and 20 landings in the previous 90 days. (Apparently, to their credit, the Swedes take the crew concept seriously. — RD)
The ground controller had held a controller license for well over 16 years at the time of the incident.
All of the conversations between ATC and the crew were recorded and are available through German Federal Bureau of Aircraft Accidents Investigation (BFU) records. The airfield surface movement radar recordings were not available to the BFU. According to the air navigation service provider, the radar data had been recorded but was deleted 10 days after the incident due to storage capacity reasons.
The 12-year-old aircraft was equipped with an FDR and CVR.
Debriefing of the crew showed that the PIC was also to be the PF on this leg, while the copilot was the monitoring pilot and handling PNF duties. Darkness had settled when they started their taxi, with the copilot talking to the controller. While taxiing to the lineup end of the runways, the controller asked the crew if they would like to use 26L for departure as she would be able to get them off quicker from that runway. Naturally the crew accepted that proposal.
As the Gulfstream was approaching the hold short area on the north side of the runways, the pilots were instructed to contact Tegel tower. Later, when the ground controller was debriefed, she stated that there had been no coordination discussion between her and the tower controller concerning the Gulfstream. This coordination discussion was standard procedure for aircraft coming from the northern apron. Due to an incorrect assumption by the ground controller that the GIV was on the south side of the runways, this discussion did not take place. As a result, the ground controller passed on her confusion and lack of situational awareness to the tower controller.
After the transfer took the traffic away from the ground controller, she shifted her attention back to some activity that was occurring on the southern side of the airport.
Due to the lack of coordination, the ground controller was not aware the tower had cleared another airplane to land on 26R. She later assessed the air traffic volume prevailing at her workstation at the time of the incident as “low.” She further stated that the workload for the previous few hours had been what she would describe as “medium.” Taped conversions confirmed that in the time between when the Gulfstream taxied and when it came to a stop to clear up the confusion, the tower had talked to seven airplanes through 29 radio transmissions. The tower controller stated that she considered the traffic situation “rather complex.” There was also a seam or pillar in the tower’s glass glazing that blocked the visibility of the NE CAT II/III holding position.
Subsequently it was confirmed that at the point of initial contact, the tower controller assumed the Gulfstream calling was the aircraft taxiing to the end of 26L from the southern parking area. In fact, that airplane had already been transferred to tower control. It was “usual operating procedures” for aircraft coming from the south side for takeoff on 26L be transferred to the tower without coordination.
It was later determined that the controller could have assumed by the call sign “Swedforce” that the airplane was coming from the military apron on the north side of the runways as this was the customary parking place for military operations. Unfortunately, the controller assumed that the aircraft transmitting as “Swedforce” was on the south side of the complex.
Further review of the tapes verified the GIV crew’s feeling that their airplane had been spotted and its position was known to the ATC controllers. The confusion, on the part of the copilot, is assumed by the safety agency as he requested confirmation that their clearance for Runway 26L had not included the permission to cross 26R. In looking around, the crew noticed the aircraft approaching 26R and one of those aircraft requesting a “wind check.”
“Tower Swedforce . . . approaching CAT three holding runway two six right.” The tower controller then cleared the aircraft to “line up on runway two six left.” The copilot answered with “line up, eh, runway two six left . . . and tower . . . confirm cleared to cross.”
The controller responded, “There is no need to cross two, eh, just line up runway two six left.” The copilot answered “Line up, eh, two six left. . . .”
Less than 4 sec. later, the crew of the airplane on final approach to 26R requested another “wind check.” The requested information was passed.
The other airplane, which was taxiing from the southern apron on taxiway SE in an easterly direction, contacted tower at about this time.
“Tegel tower . . . taxiing to the holding point runway two six left.” The controller asked, “Please confirm do you request two six right for departure or do you want to depart on the left side?” The situational furball was wound very tight at that time.
The PIC of the Gulfstream realized the situation was not right and that his copilot was confused by the received clearance and had queried the controller. This caused him to stop the aircraft. When he looked toward the final approach area of 26R he noticed several approaching aircraft. He estimated the first of them was extremely close and therefore kept his plane motionless as he tried to take in the problem unfolding. Finally, he felt it necessary to take over the communications from the copilot and transmitted.
“This is Swedforce. We are coming from the military apron and to get to the two six left, we need to cross two six right.” The controller, after a brief pause, came back with “Ah, Swedforce. . . I am sorry, so I want you to hold short of runway two six right please.”
The crew acknowledged the instruction, and in the debriefing made it clear the pilot in command had brought the airplane to a stop well before the required position on Runway 26R. The tower controller later confirmed she had assumed the Gulfstream was taxiing from the southern side of the runways.
The BFU later stated the lack of surface radar recordings prevented determining if the radar had been read correctly by the controller, but they felt the transmissions made and the positions given should have alerted her to the location and direction of the taxiing GIV on that radar.
The BFU found the cause of the incident was ATC issuing a clearance on the basis of inadequate situational awareness. It felt the restricted view from the tower of the area involved and insufficient use of the airfield surface movement radar contributed to what could have been disastrous.
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