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CASE STUDY
The Intercept Of N47BA

On October 25 1999, about 12:13 central daylight time (CDT), a Learjet Model 35, registration N47BA, operated by Sunjet Aviation, Inc., of Sanford, Florida, crashed near Aberdeen, South Dakota. Onboard was American golfer Payne Stewart along with three other passengers and two pilots. This incident offers a valuable case study for considering the performance of the air defense system on September 11 because it is the only time in the ten years prior to the 9/11 attacks that the FAA requested military intercept of a civilian aircraft over the continental United States.

This event is of particular interest in relation to 9/11 because it has previously been cited by proponents of an alternative explanation as evidence that the US Air Defense System did not function as it was designed to on 9/11. The reality is that close inspection of this tragedy reveals just how unequipped the system was to deal with civil airliners being used as weapons.

Those who bring up the intercept as an example of the system working as it was designed to tend to emphasise those aspects that are common with the 9/11 Attacks ; a civilian aircraft flying over domestic United States airspace fails to respond to Air Traffic Controllers who then dispatch fighter aircraft to intercept the unresponsive aircraft and determine what the situation is.

However what makes this intercept so valuable is not the similarities, but the differences. These can be divided into three broad categories ; the opportunity for intercept, the ease of intercept, and the actual operational nature of the intercept.

The opportunity for intercept is most fundamentally a function of time. The more time is available, the greater the opportunity for intercept, and the more likely a successful intercept is. In both the case of N47BA and the four flights hijacked on 9/11, time was limited ; eventually the LearJet would run out of fuel, and eventually the hijackers would find their targets.

In the example of N47BA, the first failure to respond occurred at 0933EDT. The aircraft crashed at 1213CDT – a full three hours and forty minutes later. In contrast, as we will see later American Airlines Flight 11 was in the air for only 47 minutes, United Airlines was in the air for 49 minutes, American Airlines Flight 77 was airborne for 77 minutes, and United Airlines Flight 93 was airborne for 81 minutes. Had UA93 continued to its intended target in Washington DC it is estimated it would have arrived between 10:10 and 10:20 EDT, resulting in a total flying time of up to 98 minutes.

The opportunity for intercept is further reduced by considering when each flight was actually hijacked, and even further by when Air Traffic Controllers first suspected the aircraft had been hijacked. Taking these factors into account the longest opportunity for intercept for any of the flights on 9/11 was 33 minutes for AA11. The discrepancy between the intercept of N47BA and the events of 9/11 becomes clear when you consider that the combined flight time between first suspicion of hijacking and impact for all four flights on 9/11 is shorter than the flight time between loss of contact and impact for N47BA alone.

Another important aspect to consider is ease of intercept. The circumstances of N47BA’s distress is detailed in the official National Transport Safety Board (NTSB) Aircraft Accident Brief. On October 25, 1999 N47BA departed Orlando Fl. For Dallas Tx. At 0927EDT, Jacksonville ARTCC instructed N47BA to climb and maintain a flight level of 39,000ft. This instruction was acknowledged by the pilot. At 09:33EDT the aircraft was instructed to change frequencies and contact another Jacksonville ARTCC controller. The aircraft did not respond to this transmission, and failed to respond to the controller’s five attempts to contact the flight over the next 4 ½ minutes.

The next incident in the NTSB report is the arrival of a USAF fighter aircraft to within 8nm of N47BA at 09:52CDT. At 09:54CDT the lone fighter approached to within 2,000ft and attempted to make radio contact, and at 10:00CDT the fighter pilot began a visual inspection. Between the last transmission from N47BA and initial intercept, 85 minutes elapsed. In this same space of time on 9/11 each of the four flights departed from international airports, attained cruising altitude, was hijacked, turned around, flown towards intended targets, and crashed.

However this discrepancy alone does not tell the entire story. The aircraft that initially intercepted N47BA was not an armed NORAD alert fighter. It was an unarmed F-16 from the 40th Flight Test Squadron based at Eglin Air Force Base in Florida. The aircraft was also already in the air at the time, and happened to be in the vicinity. It is not unusual for Air Traffic Controllers to use the pilots of nearby aircraft as their “eyes” in the event of an incident with another flight. On 9/11 several military and civilian pilots were asked to look out for the hijacked aircraft (including the pilots of UA175 who would, in an act of tragic irony, themselves become victims of a hijacking only minutes later), and at least two were diverted from their flight paths by ATC to investigate.

As such the initial intercept of N47BA cannot be considered a scramble. It was nothing more than the diversion of a locally available aircraft that was capable of locating the LearJet and moving close enough to inspect it. This intercept was requested directly by the mission coordinator at Jacksonville ARTCC, and was not a formal request for military assistance.

These aspects made the intercept easier from the perspective of the Air Traffic Controller, however several other aspects made the intercept easier from the perspective of the fighter pilot as well. N47BA was flying at about 46,000ft in level flight on a Northwest heading. The aircraft did not deviate in any way from this flight path from the moment that communication was lost, other than to fluctuate in altitude. N47BA also maintained an operational and correctly functioning transponder at all times. As previously discussed the transponder relays vital information to the FAA such as flight number, altitude, airspeed and heading. The transponder is also of benefit to the fighter pilot as all military combat aircraft are fitted with an Identification Friend-or-Foe (IFF) interrogator which enables them to directly interrogate the aircraft’s transponder (rather than relying on position reports from the FAA).

As previously mentioned the F-16 that initially intercepted N47BA was already airborne at the time and in the vicinity. This also made intercept easier for the pilot as he was already at altitude and in close proximity to the target aircraft.

The last aspect to consider is the operational nature of the intercept. As I have already discussed, the protocol for requests for military assistance to civilian authorities is strictly regimented by a series of orders. While under immediate response conditions peaceful and humanitarian efforts are permitted, this does not include the escort of hijacked aircraft, which is addressed by its own regulations. Likewise this does not include military assistance in a law enforcement capacity, nor military assistance in the event of a major terrorist incident. In both cases military assistance is strictly controlled in accordance with US law.

In the case of N47BA there was no grounds for air traffic controllers to consider the incident an aircraft hijacking or terrorist attack. It was instead an airborne emergency. In contrast FAA controllers on 9/11 immediately suspected AA11 was a hijacking, and after the crashing of UA175 they knew they were dealing with a major terrorist incident with many other suspected hijackings underway.

The circumstances of the intercept of N47BA were therefore very different from the circumstances on 9/11 and required a very different process for responding. In numerous ways this earlier incident facilitated a much easier interception. Despite this, had the intercept procedure on 9/11 followed the sequence that occurred in the case of the N47BA intercept, none of the hijacked aircraft would have been successfully intercepted.

The lessons offered by the intercept of N47BA do not begin and end with the successful intercept of the LearJet by a lone F-16, 85 minutes into the emergency. According to media reports after the incident, at about 09:08CDT the FAA requested assistance, and two F-16s from the 148th Fighter Wing at Tyndall Air Force Base in Florida were diverted to intercept the Learjet. This was the first involvement of interceptors, and it occurred 35 minutes after communication was lost. Had the FAA delayed this long before requesting an intercept for the flights on 9/11, all four would have crashed before the request was even made.

These fighters from Tyndall failed to catch up with the Learjet. Meanwhile at about 09:22CDT the FAA diverted the F-16 from Eglin, accompanied by a Fairchild A-10 Thunderbolt II, to intercept the Learjet. They reached within 8nm of the Learjet half an hour later, but the slower A-10 fell behind so that the F-16 intercepted N47BA alone at 09:54CDT. The F-16 departed the Learjet at 10:12CDT as it was low on fuel.

Another intercept request was not made until 10:59CDT, when four Oklahoma Air National Guard F-16s on a training mission with a KC-135 tanker aircraft were directed to catch up with the Learjet. Like the fighter from Eglin, these fighter aircraft were unarmed.

This request was followed at 11:03CDT by a scramble of two unarmed F-16s from the North Dakota Air National Guard at Fargo. At 11:13CDT two of the Oklahoma ANG F-16s made contact with the Learjet and inspected it.

At 11:15CDT the two Oklahoma fighters were joined by the North Dakota ANG fighters. The Oklahoma ANG and North Dakota ANG fighters remained in close proximity with the Learjet until it crashed 23 minutes later.

The Learjet spent 3 hours and 40 minutes flying uncontrolled and unresponsive across US airspace, yet it was only escorted by fighters for 1 hour and 18 minutes of this time. It took the FAA 35 minutes to request military assistance, and when they did, a total of four different flights of fighter aircraft were diverted or scrambled to intercept the Learjet. The first failed to intercept, the second took 32 minutes to intercept, the third took 14 minutes to intercept, and the intercept time for the last flight was 47 minutes. Of these four flights, all but the last one were in the air at the time their assistance was requested, and none were armed. One minute before the aircraft crashed, and 3 hours and 39 minutes after contact with the aircraft had been lost, two armed fighters at Fargo, North Dakota were put on alert ; the first instance of armed aircraft being considered to escort the Learjet.

According to numerous media reports at the time of the incident, the Pentagon never considered shooting down the aircraft at the time of the incident, and although a discussion began about an hour into the incident over what to do if it appeared the aircraft would crash in a heavily populated area, estimations of where the aircraft would run out of fuel indicated it would be over a rural area.

The intercept of N47BA over the continental United States in 1999 provides us with vital information regarding the practical functioning of the air defense system. Despite numerous incident-specific characteristics which favoured a rapid and successful intercept in comparison with the hijackings of 9/11, the outcome of that earlier incident indicates that under similar circumstances any attempted intercept on 9/11 would have failed. Once it is taken into account that numerous aspects of the 9/11 events made a successful intercept significantly more difficult, it is no surprise that none of the four airliners were intercepted by the military

Voici la fiche wiki si ca vous interesse : http://en.wikipedia.org/wiki/1999_South_Dakota_Learjet_crash