Recommendation Comes After Of CO MU-2 Accident

An urgent plea from the NTSB to the FAA... fix the software in the audible alert link between en route control centers and local control towers, and eliminate barriers that prevent the transfer of such warnings when an aircraft if more than five miles away from the airport.

That very glitch, says the NTSB, prevented approach controllers at Denver International from transmitting an altitude-terrain warning to the tower at Centennial -- and eventually to the pilot of an MU-2 on a night IFR approach last year.

According to a safety bulletin issued by the safety board this week, eleven aviation accidents have been linked to software problems with the Minimum Safe Altitude Warning system. MSAW is used to warn controllers and pilots of terrain hazards.

The NTSB says controllers at DEN got the warning early on the morning of August 4, 2005... accompanied by an on-screen alert. But because of the delay... the MU-2 continued toward the hazard until it was within five miles of Centennial.

The controller at Centennial relayed the warning to the pilot within five seconds... but never got a reply. Two seconds after he issued the warning... the MU-2 hit the ridgeline, killing the pilot.

The FAA won't yet talk about the issue, but controllers in nearby towers will.

At Jefferson County Airport, FAA tower supervisor Sharon Wilkins tells the Denver Post she's instituted a new procedure. If Denver approach controllers get a MSAW warning involving an aircraft in her tower's vicinity... they are required to give her a call instead of relying on the automatic system.

And at Centennial... officials say they're unaware of any new procedures involving MSAW activations.

FMI: www.ntsb.gov