80-82 SAFETY SENSE.qxp 26/11/2019 15:08 Page 80

SAFETY SENSE COLLIDING WITH A GLIDER: IFR IN UNCONTROLLED

While uncommon, mid-air collisions are disastrous and often fatal when they occur. Michael R. Grüninger and Capt. Andreas Grauer analyze contributory factors and key strategies for avoiding such collision

riday, 12th February 1999, was a glider was enjoying the steady lami- Descending through FL 85, the chilly day in the south of France. nar flow. Still at Flight Level (FL) 290 commander took control of the air- F Strong northerly winds were and preparing for the approach, the craft, disconnected the autopilot and blowing and generating waves. Glider pilot monitoring of the AF flight lis- executed an immediate escape pilots love such waves as they provide tened to Montpellier ATIS “Hotel”, maneuver to the right. One minute them with a constant and reliable which warned of glider activity in the later the A320 was cleared to updraft to reach height and stay in approach sector. descend to altitude 5000 ft. The com- the air for many hours. At 15:31, ACC Marseille authorized mander notified ATC about the air- Using this opportunity, the pilots of the A320 to descend to FL 120. prox. a Grob 103 glider, F-CGXB, let them- At 15:36, Montpellier Approach At this stage, the crew of the A320 selves be towed out of Saint Martin cleared the A320 to further descend was not sure whether they had collid- de Londres airfield towards the Pic to FL 80 on course to the Very High ed with the glider or not. Saint Loup. From there, the G103 Frequency (VHF) Omni-Directional At the same time the pilots of the G continued to the lee-side of the Range (VOR) Montpellier 103 felt a hard hit. Alerted and wor- Seranne Mountain where the laminar Méditerranée (FJR) on a magnetic ried about the hit, they looked around flow was strong above 6000 ft. The heading of 136°. The A320 and saw an A320 in descent perform- glider entered the flow and slowly approached FL 80 three minutes later ing a right turn. The situation was progressed in the direction of North- at 15:39. clear to them immediately. Northeast. The A320 now flew in Airspace The sailplane pilots considered FATAL Just 7 minutes later, at 14:59, Air Class G. The Airway G6 was located 7 abandoning the glider and jumping to One of the most France flight number AF 755x0, an nm to the east of the position of AF safety by using their parachutes. hazardous Air France Airbus 320 registered as 7550. However, they carefully tested the consequences F-GJVG, took off from Paris Orly One minute later, at 15:40, the remaining functionality of the glider of a loss of Airport with destination Montpellier. A320 commander observed a glider and found that with due care a safe The first officer was pilot flying and flying below them on the left. Soon return to the airfield might be possi- between aircraft the commander pilot monitoring. after, the copilot, announces that he ble. By avoiding abrupt maneuvers is mid-air Montpellier Méditerranée Airport is has another glider in sight right in and high aerodynamic stress, the collision. located south of the area where the front. pilots landed the G 103 safely.

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SAFETY SENSE

Once on the ground, the pilots saw The glider was in wave flight at FL 80 classes they are going to cross on their that the upper left horizontal stabiliz- and the A320 on arrival to Montpellier routes and identify the implications for er was severely damaged. Airport. The at the collision avoidance. The A320 also landed safely. But the moment of the mid-air collision was In the unmanned aircraft world, see pilots had doubts whether they had in Class G. and avoid is replaced by detect and fact collided with the glider or just The A320 successively crossed vari- avoid. This is an automated system, barely missed it. During taxi to the ous Airspace Classes in fast sequence: where airborne sensors detect obsta- gate, the commander informed ATC ❍ From cruise to initial descent: cles and other flying objects and auto- about his doubts. ATC confirmed the Class A matically initiate an escape maneuver. collision and informed the comman- ❍ Descending below FL 195: Class D Of course, this is not possible in der that the glider had landed safely controlled airspace manned aircraft operation. and that no personal injuries were ❍ Passing FL 115: Class G uncon- Detection is also provided in manned reported. trolled airspace aircraft, by a Traffic Alert and Collision Once the Airbus was parked, an ❍ The mid-air collision occurred at Avoidance System (TCAS). TCAS inspection of the wings revealed that FL 80 in this class G airspace. Class G detection would have worked at least the leading edge of the left wing was airspace is . In in those cases, where conflicting air- damaged. class G airspace, operations may be craft are all equipped with a TCAS or conducted under IFR or VFR. ATC another compatible collision avoidance Separation by ATC has no authority, but VFR minima are system. Separation of air traffic, and the to be known by pilots. Traffic At the time of this serious incident, methods of separation, is the key to Information may be given by ATC as commercial aircraft were not yet the organization of the airspace sys- far as is practical in respect of other required to be equipped with Airborne tem. Understanding these separation flights. Collision Avoidance Systems. concepts is crucial for pilots. Pilots ❍ Minutes after the collision: Class D “See and Avoid” is rarely described in should never feel to be protected by controlled airspace detail in the Operating Procedures of ATC separation, when in fact they are ❍ Descending through 5700 ft: Class most operators since they operate not. E controlled airspace mainly in controlled airspace. In 1990, ICAO adopted the current ❍ At about 4900 ft: Class D, destina- (ATC), Automatic airspace classification scheme. It tion airport Terminal Information Service (ATIS) introduced seven airspace classes. ❍ Then the A320 flew until landing in broadcasts and/or Notices to Airmen Classes A to E are so-called con- this Class D controlled airspace. () often provide information trolled . Classes F and G are Problems with separation between about VFR traffic in the vicinity. uncontrolled airspaces. VFR and IFR traffic often occur on It is important that the pilots are However, controlled airspace does- charter flights and scheduled services aware of their responsibility for colli- n’t necessarily imply that ATC is to smaller airports. sion avoidance, when flying in uncon- responsible for or ensures separation The problem is even bigger in trolled airspace and in Class E con- between aircraft. Business Aviation where passengers trolled airspace, where ATC does not In general, the classes are defined in charter a business jet specifically separate IFR from VFR traffic. terms of flight rules and interactions because it enables them to fly directly Fortunately, this particular mid-air between aircraft and ATC. For ICAO to small airfields, as close as possible collision between such unequal aircraft airspaces the responsibility for avoid- to their destination, which sometimes did not result in harm to persons. ing other aircraft is either assigned to does not even have any instrument ✈ ATC or to the aircraft commander, facilities. Due to the great difference in depending on the airspace class. speeds and the fact that gliders and In Class E airspace, ATC separates very light aircraft are sometimes diffi- Michael R. Grüninger is Managing IFR from IFR traffic, but not from cult to spot in the air, maintaining visu- Director of Great Circle Services VFR traffic. In Class G airspace, no al separation is a challenge. (GCS) Safety Solutions and Capt. separation is provided by ATC. Andreas Grauer is the Deputy See and Avoid Managing Director of GCS. GCS Flying IFR through “See and Avoid” is recognized as a assists in the whole range of planning Various Classes of Airspace method for avoiding collision when and management issues, offering cus- It is difficult for a pilot to constantly weather conditions permit and require tomized solutions to strengthen the be aware of the classes of airspace that pilots should actively search for position of a business in the aviation crossed while preparing for an potentially conflicting traffic, especially market. Its services include interim approach and looking outside in when operating in airspace where all and start-up management, training compliance with the “see and avoid” traffic is not operating under the and auditing (IS-BAO, IOSA, EASA), rule. instructions of ATC. consultancy, manual development and The mid-air collision between the The operator could include aware- process engineering. GCS can be Grob 103 glider and the Air France ness training of airspace classes in reached at www.gcs-safety.com and A320 is a good example for the diffi- their route and aerodrome competence +41-41 460 46 60. The column Safety culty of pilots to constantly be aware training. Such training might provide Sense appears regularly in BART of the types of airspace they cross. pilots a clear picture of the airspace International since 2007.

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