Superstall recovery
Joined: Mar 2002
Posts: 22
Likes: 0
From: Buffalo, NY
In the book "Air Disaster, Volume 1", Macarthur Job provides a fairly detailed account of the Staines accident. As stated in an earlier thread, the crew did, indeed, disengage the stick pusher. The article goes on to state that, via FDR data, the cause was traced to retracting the leading edge droops at too low an airspeed. Figures in the article are listed as 162 knots @ 1770 feet when droop retract occured.
What I find curious about this accident, is the number of qualified personnel on the flightdeck at the time. The text lists captain, first officer, a second officer in the monitoring pilot's position, and a BEA Vanguard captian, who was qualified on the Trident, in the jumpseat behind the pilot. I can't help but wonder why no one saw the premature droop retraction.
Further along in the same book, another deep stall, this one in a Boeing 727-200, is recounted. This accident was apparently caused by an iced up pitot head. CVR transcripts point to a failure to activate pitot heat during the pre-flight check, which lead to erroneous rate of climb and airspeed indications. At one point, readings indicated a 5000 fpm climb at 340 knots. Thinking that the spirited performance was due to a light aircraft (ferry flight), the crew pulled back on the control column to prevent excessive airspeed. At around 24,800 ft, 30 deg nose up attitude, and 165 knots, the stick shaker activated. Believing that the airspeed readings were correct, the crew mistook the stall warnings for Mach buffet. The text goes on to state that the aircraft stalled, and the disturbed airflow over the wing blanketed the elevators, rendering them useless. Apparently, this phenomena is peculiar to the configuration of T-tail aircraft.
Both accounts made for some very chilling reading.
What I find curious about this accident, is the number of qualified personnel on the flightdeck at the time. The text lists captain, first officer, a second officer in the monitoring pilot's position, and a BEA Vanguard captian, who was qualified on the Trident, in the jumpseat behind the pilot. I can't help but wonder why no one saw the premature droop retraction.
Further along in the same book, another deep stall, this one in a Boeing 727-200, is recounted. This accident was apparently caused by an iced up pitot head. CVR transcripts point to a failure to activate pitot heat during the pre-flight check, which lead to erroneous rate of climb and airspeed indications. At one point, readings indicated a 5000 fpm climb at 340 knots. Thinking that the spirited performance was due to a light aircraft (ferry flight), the crew pulled back on the control column to prevent excessive airspeed. At around 24,800 ft, 30 deg nose up attitude, and 165 knots, the stick shaker activated. Believing that the airspeed readings were correct, the crew mistook the stall warnings for Mach buffet. The text goes on to state that the aircraft stalled, and the disturbed airflow over the wing blanketed the elevators, rendering them useless. Apparently, this phenomena is peculiar to the configuration of T-tail aircraft.
Both accounts made for some very chilling reading.
