Airline warned of deadly #23 runway before crash.

Southwest Airlines warned its pilots just weeks before the crash of a commuter flight in Buffalo about safety issues with so-called instrument approaches at the airport. The warning concerned runway 23, the same runway the crashed commuter plane was lined up to use.

Instrument approaches are those in which pilots use cockpit displays to line up their aircraft with the runway when visibility is low.

The alert, reissued Wednesday by the airline's pilot association, warned Southwest pilots there was a "potentially significant hazard" concerning the instrument landing system's glide slope guidance signal for runway 23.

The airline advised, "Pilots who are preparing to configure and land have the potential to experience abrupt pitch up, slow airspeed, and approach to stall if conditions present themselves in a certain manner."

Southwest Airlines spokesperson Linda Rutherford said an earthen dam at the end of the runway was interfering with the signal being sent to inbound flights. Rutherford would not confirm if any of Southwest's recent flights into Buffalo experienced problems on approach.

"We often put out alerts on obstructions to a navigation aid," Rutherford told CNN. She also pointed out, though landing on the same runway, Southwest Airlines flights approach runway 23 from the north, turning right, while the crashed Colgan Air flight was approaching from the south turning left. Rutherford called that distinction important.

The National Transportation Safety Board told CNN the agency was "aware" of the Southwest Airlines alert, but would not comment further. The Federal Aviation Administration is looking into the matter.

The alert from Southwest Airlines advises pilots that the problem could cause the planes navigational system to interpret data "in such a way as to result in a nose-up pitch and loss of airspeed."

Flight data recorders obtained by the NTSB of the crashed Colgan air flight 3407 show during its approach to runway 23, the twin turbo prop Dash-8 pitched up 31 degrees before going into a stall due to lack of airspeed.

Southwest Airlines Pilot Association told its pilots the "issue is being addressed on several levels in an attempt to address procedures, facilities, and communication regarding this matter." the alert advises any pilots experience trouble to contact the association's safety office.
"23 is considered lucky, unlucky, sacred to the goddess Eris, sinister, sacred to the unholy gods of the Cthulhu Mythos, or strange".