Feb. 12, 2014
The FAA this month streamlined procedures for certification of angle of attack (AOA) indicators, a move safety advocates hailed as a significant step forward in combating accidents caused by departure from controlled flight.
The new policy, which in lieu of rulemaking will be in effect for the next three years, greatly reduces the cost of installing an AOA indicator in general aviation aircraft.
“We have eliminated major barriers so pilots can add another valuable cockpit aid for safety,” said FAA Administrator Michael Huerta in announcing the new policy. “These indicators provide precise information to the pilot and could help many avoid needless accidents.”
AOA is the angle between a plane’s wings and the wind that lifts them. If the angle of attack is too great, the wing can stall, sometimes leading to a loss of control and possibly dangerous spins.
The new policy calls for manufacturers of AOA indicators to build them according to standards set by ASTM International (The American Society for Testing and Materials), and then apply to the FAA for approval of the design by stating that the equipment meets those standards.
The systems would be clearly placarded as being for reference only and not for use as a primary flight instrument.
Tim Short, a flight instructor and former military pilot who now flies for ExpressJet, welcomed the FAA policy shift as a way to bring AOA awareness to all pilots – but especially those who are just learning to fly.
“One of the reasons having AOA in general aviation aircraft used for training is to produce a culture of pilots who grow up having AOA as part of their scan,” Short said.
The use of AOA indicators is especially important in business aircraft, according to Rich Stowell, eight-time Master Flight Instructor, author and the 2014 Safety Team Rep of the Year.
“In business aircraft, you’re often operating at flight levels,” Stowell said. “In the process of transitioning from hard instrument or night flight or simply breaking out at minimums, AOA is crucial to providing the big picture in terms of energy management and awareness.”
Both Short and Stowell pointed to high-speed, high-altitude flight, where aircraft often operate near the “coffin corner” – between the aircraft’s stall speed and the buffet that signifies supersonic flight.
“So using an AOA indicator can really help reduce incidents of high-altitude loss of control, which can be more common than is generally acknowledged,” Short said, adding, “This is the missing piece to the puzzle. This is that piece which will help airmanship levels across the spectrum of capabilities.”
The next step, Short said, is to gain greater awareness of what information can be derived from the AOA indicator.
“To a pilot not trained to understand its indications, it becomes just another needle flopping around and doesn’t mean much,” said Short.
While instruction in AOA indicator use generally requires three to five hours in the cockpit, as well as some ground instruction, Short said all pilots should become familiar with its value. Stowell said that effort needs to begin with flight instructors themselves.
“The corps of flight instructors is generally not qualified or is underqualified on AOA awareness and stall/spin awareness,” Stowell said. “Part and parcel with the movement to increase AOA awareness must be training the instructors.”