Help out of the black hole

Air Safety Week, August 26, 2002

The July 26 crash of a Federal Express [FedEx] B727 freighter at Tallahassee shows the utility of forward looking terrain avoidance warning (TAWS) technology, also known as enhanced ground proximity warning system (EGPWS). Federal Express has been among the most proactive carriers to design, test, certify and install EGPWS on its fleet of 325 aircraft. But the job was only about two-thirds complete, and the B727 and DC-10 fleets were next in line - too late to help prevent the crash at Tallahassee.

Had the accident airplane been equipped with EGPWS, the crew would have received about 15 seconds warning of impending ground impact.

In the early morning darkness the crew was descending into striated patches of fog. At about 15 minutes before sunrise, it would be brighter at altitude but would get increasingly dark near the ground. There was no tower operator on duty, so the crew had to "key" the runway approach lights to turn them on, which they did at about 320 seconds before impact. If the airplane's landing lights were activated, the backscatter of white light from the fog can be quite disconcerting, said one pilot who's been in this situation, and the altitude might be allowed to drop - leading quickly into an underrun situation. The crew began clipping trees about 0.65 NM from Runway 9, with full impact at 0.5 NM.

Impact and fire destroyed the airplane, but the three-man crew thankfully survived.

The 10 crew and passengers of a U.S. Air Force MC-130HC special operations airplane were not so fortunate, striking Monte Perucho in Puerto Rico during an Aug. 8 night flight. As one source remarked, the accident scene looks similar to the 1995 accident at Cali, Colombia, when an American Airlines B757 ploughed into the ridgeline during a night descent. "Like a lawn mower gone wrong," was the operative phrase. The Monte Perucho crash marked the fourth controlled flight into terrain (CFIT) accident for military C-130 aircraft over the past year.

The aircraft that crashed Aug. 8 was equipped with the old "classic" ground proximity warning system, which does not provide the greater warning of the latest EGPWS "look ahead" technology. Indeed, sources advise that for low level operations, a cockpit switch disables or sets the alert/warning to very short radio altitudes. The enhanced technology can be set to work at low levels and provides a display of terrain in yellow or red to warn of ground ahead and above the flight path. Indeed, this feature helped to "save" an Alaska Airlines [ALK] B737 during a night approach into Tucson, Ariz., last January (see ASW, March 25, EGPWS terrain display).

Although not fatal, the crash at Tallahassee underscores the continuing hazard posed by CFIT accidents. As measured from the summer of 2001 to the summer of 2002, more than 400 passengers and crew have been killed in such accidents in the civilian sector. From this grim tally, Don Bateman, chief engineer of flight safety systems at Honeywell, offered a few pertinent observations:

* Six of the nine CFIT accidents occurred during non-precision approaches.

* None of the accident aircraft was equipped with EGPWS.

* MSAW (minimum safe altitude warning) system coverage is being disabled if the pilot accepts a 'visual approach.' There have been some very near misses at night for large commercial aircraft that have visual contact with the runway. Five incidents at Tucson, Ariz., as an example.

* Getting the most effectiveness out of EGPWS:

* Periodically update to the latest EGPWS software and databases. They are free and available (see www.egpws.com).

* Encourage pilots to have terrain obstacles displayed on at least one navigation display or weather radar display during flight and on short ranges during takeoff and landing.

* Enable the display of 'obstacles' and 'peaks.'

* Encourage the State to publish the location and elevation of obstacles in digital format in WGS-84 [world geodetic system] coordinates.

* Aggressively eliminate unwanted warnings. Honeywell will help you. >> Bateman, e-mail, c.don.bateman@honeywell.com <<

Large Commercial Aircraft CFIT Losses Summer 2001 to Summer 2002
Date           Location                Aircraft  Toll
Nov. 24, 2001  Zurich, Switzerland     RJ-100    24 killed of 33 aboard
Nov. 27, 2001  Port Harcourt, Nigeria  B747      1 of 14
Jan. 18, 2002  Near Ipiales, Colombia  FH-227    26 killed
Jan. 28, 2002  Tulcan, Ecuador         B727      92 killed
Feb. 12, 2002  Khoramabad, Iran        TU-154    117 killed
Apr-02         Busan, South Korea      B767      130 killed of 167 on board
7-May-02       Tunis, Tunisia          B737      18 killed of 62 aboard
1-Jun-02       George, South Africa    HS-748    3 killed
26-Jul-02      Tallahassee, Fla.       B727      0 of 3 on board
Total  9 accidents  411 fatalities

Military C-130 CFIT Losses Since 1996
Date        Location            Model    Toll
Aug. 1996   Jackson Hole, Wyo.  C-130H   9 killed of 9 aboard
Dec. 1999   Kuwait              C-130H   3 killed of 20 aboard
Sept. 2001  Niteroi, Brazil     C-130    9 killed of 9 aboard
Jan. 2002   Shamsi, Pakistan    KC-130R  7 killed of 7 aboard
Feb. 2002   Afghanistan         MC-130P  0 killed of 7 on board
Aug. 2002   Monte Perucho, PR   MC-130P  10 killed of 10 aboard
Total: 38 fatalities  Source: Honeywell