PC-12 and BN-2 pilots unaware of one another’s presence before serious Caribbean airprox

Language conflict and absence of transponder cited after Islander overtaken by faster aircraft on same route.
French investigators have disclosed that a Pilatus PC-12 passed just 100ft directly above a Britten-Norman BN-2, with neither crew aware of the other’s presence, as they were flying the same inter-island route in the Caribbean.

The turboprops were operating commercial flights from Saint Martin to Saint Barthelemy on 28 December 2024.

French investigation authority BEA states that the BN-2 took off from Sint Maarten Princess Juliana airport’s runway 10, followed about 2min later by the PC-12.

The route to Saint Barthelemy – a distance of 17nm – is flown at 1,500ft.

According to the inquiry, the BN-2 flew at 130kt groundspeed. But the PC-12 was faster, at 200kt, and it gradually caught up with the other aircraft.

“Juliana tower…provided no traffic information regarding the presence of the other flight, even though both aircraft were on identical trajectories,” the inquiry adds.

BEA found the transponder of the BN-2 was not functioning, for reasons that could not be determined. The aircraft was not required to have a collision-avoidance system, and none was installed.

As a result, the PC-12 pilot “saw nothing” on his collision-avoidance system screen which “confirmed his belief that he was alone in the air”. This, and other factors, meant that, although he was looking outside, he was “not actively searching for another aircraft”, says the inquiry.

Each aircraft contacted the aerodrome flight information service, in the vicinity of the mandatory reporting waypoint GROUPER.

But while the PC-12’s radio communications were in French, those of the BN-2 were in English. Both crews informed that they would call again at the next waypoint, but this had different names – PAIN DE SUCRE and SUGARLOAF – in the respective languages.

No traffic information was provided during the radio exchanges.

Some 2min later the PC-12 pilot disengaged the autopilot and commenced a descent to Saint Barthelemy, reducing speed to about 140kt and extending the flaps and landing-gear.

Within a few second the BN-2 captain contacted the AFIS officer and informed that a PC-12 had passed overhead, testifying to the inquiry that it was directly overhead at a distance of less than 100ft.

“The PC-12 pilot was surprised by the message, having seen nothing and having received no traffic information,” the inquiry says. “He then looked for the other aircraft and spotted the BN-2 to his right, about 50m away and 50ft below.”

BEA says the BN-2 aborted its approach and entered a right turn, adding: “[The pilot] expressed his displeasure over the radio about what had happened, and in particular the use of French on the radio.”

After visually sighting the BN-2, the PC-12 pilot made a left-hand orbit and reported that he had not been informed of the traffic.

BEA highlights the “fragility” of the collision-prevention strategy in the region, which is based on see-and-avoid, despite the fact that traffic of heterogeneous performance is dense, constrained, and “frequently converges”.

None of the five occupants on the SXM Airways BN-2 (PJ-SXM) or the five on the St Barth Executive PC-12 (F-ONGX) was injured.

BEA points out that there have been “significant recurring safety incidents” at Saint Barthelemy since 2023, including several near-collisions, runway incursions, and landings on occupied runways.

It states that the operational environment has a “unique combination” of features – including absence of instrument flight rules procedures, hills in the vicinity of the airports, and high traffic density – making its use “complex and challenging”.

Among measures taken since the incident to reduce risk, St Barth Executive has indicated that it has instructed exclusive use of English radio transmission at Saint Barthelemy and Saint Martin.

The post PC-12 and BN-2 pilots unaware of one another’s presence before serious Caribbean airprox first appeared on FlightGlobal.