Only a massive reserve of excess thrust will get you out of severe wind shear — and sometimes that’s not enough. In writing my last article on wind shear and inertia, I was reminded of the chilling tale of Delta Airlines Flight 191.
Delta 191 was a landmark aviation accident that shook the industry. Flight 191 proceeded much like any other airline flight, right up until the last 40 seconds.
First Officer Rudy Price was at the controls with the assistance of Captain Ed Connors and Second Officer Nick Nassick. The first sign of trouble came at 800 feet AGL while on final approach into Dallas Fort Worth with a 24 knot increasing-performance wind shear.
The crew rightly anticipated a loss of performance and pushed the trust levers “way up” as the airspeed dropped from 173 knots to 133 – a 40 knot wind shear. Despite the L-1011′s nearly 160,000 pounds of thrust, the aircraft still slowed to 119 knots and rapidly descended to the ground where it bounced and skidded into water tanks killing 134 passengers and one nearby motorist.
Recording from the Cockpit Voice Recorder
After the investigation, the NTSB concluded that Delta Flight 191 had entered a microburst. The probable cause faulted the crew for their decision to continue the approach into a cumulonimbus cloud with visible lightning and the airline for lack of specific training and procedures for avoiding and escaping low level wind shear. The NTSB also indicated the lack of real-time wind shear hazard information as another probable cause.
Despite the lack of training cited by the NTSB, this crew really did a great job. There isn’t much to wind shear escape other than applying max thrust and pitching for best climb. That’s probably going to be Vx for your aircraft unless the manufacturer or company training program specifies something else. The chilling truth about Delta Flight 191 is that sometimes you just don’t have enough power to get out of it – and that’s not a comforting thought. As with most weather-related issues, the best strategy is avoidance.