1.17.4.3 Terrain Avoidance Recovery Maneuvers
At the time of the accident, one manual issued to Korean Air flight crewmembers--the company's 747 Aircraft Operating Manual--contained written guidance on when to execute a recovery maneuver to avoid terrain. Under the section entitled "PULL UP/TERRAIN AVOIDANCE," the manual stated:[1]
The published RECOVERY MANEUVER procedure is immediately accomplished by recall whenever the threat of ground contact exists. Either of the following conditions is regarded as presenting a potential for ground contact:
- Activation of the "PULL UP" warning.
- Inadvertent windshear encounter or other situations resulting in unacceptable flight path deviations.
Korean Air's 747 Aircraft Operating Manual (page 14.20.02, dated November 2, 1992), required the following procedures for the recovery maneuver:
Aggressively position the thrust levers forward to ensure maximum thrust is attained, disengage autopilot and autothrottle (as installed), and rotate smoothly at a normal rate toward an initial pitch attitude of 15 degrees.
Do not use flight director commands.
Pitch attitudes in excess of 15 degrees may be required to silence the "PULL UP" warning and/or avoid terrain.
Note: In all cases, the pitch attitude that results in intermittent stick shaker or initial buffet is the upper pitch attitude limit (this may be less than 15 degrees in a severe windshear encounter).
Large thrust increases may result in a nose-up pitching tendency requiring forward column pressure and trim.
Monitor vertical speed and altitude. Do not attempt to change flap or gear position or regain lost airspeed until ground contact is no longer a factor.
{{x-lar1.17.5 Korean Air Accident and Incident History
The Safety Board used data provided by Airclaims Limited[2] to compare Korean Air's safety record with the records of five major U.S.-based airlines and five major Asian-based airlines. The total hull loss records for all of these airlines were calculated for a 10-year period ending December 31, 1998, using two measures of activity or exposure to
- ↑ Most U.S. airlines refer to this procedure as the escape maneuver.
- ↑ Airclaims Limited is an aviation consulting firm that collects data, in part, for the aviation insurance industry. The Airclaims Limited database is recognized by the aviation industry as a definitive source for worldwide aviation accident information. Loss data for this comparison were retrieved from Airclaims Client Aviation System Enquiry database and were current as of August 10, 1999. Exposure data were retrieved from Airclaims Limited, Jet Operator Statistics, 1999, issue 1.
