With overwhelming frequency, Part 121 pilots elect to continue an unstable approach rather than go around, according to a study conducted by the Flight Safety Foundation. The 55-page report, titled “Go-around decision-making and execution project,” cites both pilot decision-making during unstable approaches and problems with management oversight of go-arounds among Part 121 pilots. Lessons learned in the report are salient for Part 135 and Part 91 flight deck operations, as well.

“Although around 96 percent of all approaches are considered stable, of the four percent that are unstable, only around three percent of those result in a go-around,” said Greg Marshall, FSF vice president for global programs. “From this report we see that management needs to be engaged; policies need to be realistic. To do that, things need to be revised from what they are now,” Marshall told AIN. The report suggests flight departments revise their final approach and touchdown zone standard operating procedures (SOPs) for pilots, and encourages more management oversight and use of flight data analysis (FDA).

Unstable Approaches Rare, but Accidents Happen

“Not all unstable approaches are dangerous—but unstable approaches can end in accidents [many of which are survivable, unlike loss-of-control],” said William Curtis of The Presage Group, co-chair of the FSF International Advisory Committee. Curtis was a co-author of the report.

The report cites the runway overrun of a Southwest Airlines 737-300 at Burbank-Glendale Pasadena on March 5, 2000, as an example where a go-around would have prevented the accident. The captain in that accident told the NTSB that he knew as the aircraft passed through 500 feet that he was not “in the slot,” meaning the conditions had not been met for a safe landing, in this case because of excessive airspeed. He said that he understood that procedures demanded a go-around. He could not, however, explain why he did not perform one.

The interviews and data collected in the FSF report reveal that compared with pilots who decide to go around, pilots who fly unstable approaches to a landing rated their flight outcomes less positively, believed less often that they had made the right decision, and believed more strongly than go-around pilots that they should not have made the decisions they did. Essentially, many regretted deciding to continue the approach, even if no accident or incident resulted.

“We analyzed a statistically significant group of pilots who made decisions to go around, and a group of those who chose to continue. The go-around group clearly showed different characteristics; one of them was that they had briefed more on the potential threats and they adjusted more, and had more communication—collaborative decision-making was much higher. “They were ready for a go-around,” said Curtis.

A Dearth of Oversight

The study acknowledges that it struggled for management participation. Among those managers who did participate, a majority were largely unaware of unstable approach go-around compliance and policies in their own companies, even though 91 percent of the companies involved in the survey had FDA collection with evidence of compliance and non-compliance available to managers.

“There seems to be an unintended acceptance of the current state of go-around compliance by management,” said Curtis. “Both pilot groups felt the go-around criteria for their airline was not realistic for that operation, that particular day. They made their own decisions because they knew there was little oversight from management.”

For decades the industry has used the concept of approach “gates,” altitudes during descent at which key markers of a stabilized approach must be present for the approach to continue, and touchdown zone parameters. These gates are typically set at 1,000 feet (300 m) agl and 500 feet (150 m) agl. The FSF report suggests adding a final gate at 300 feet (100 m) agl.

“The safety analysis says that most properly loaded aircraft can stop a descent even at twice the normal rate, and go from flight idle to a good climb gradient safely from 300 feet,” said Marshall. Yet events unfold quickly at and below that altitude, and pilots often need to react with lightning quickness; training plays a huge part in how a crew manages the last few seconds before and during touchdown. Crews are typically trained that either pilot can call a go-around until thrust-reverser deployment. Deviation from touchdown zone parameters (long landings) possibly caused by an unstable approach or a contaminated runway, however, can raise the possibility of a potentially deadly runway excursion.

“Before, we said ‘Go-arounds are necessary here.’ Now we are saying ‘If you are a little bit outside the guidance it is OK to continue if you have reasonable expectation of being on target at the next gate,’” explained Curtis.

The report concludes that by allowing some guided decision-making during approaches and landings, pilots will be more likely to trust and voluntarily comply with written policies, in part because those policies will address the changing environment in which pilots work, where risk assessment is constant.

The report also uncovers issues with SOPs in the touchdown zone. “Active communication in the landing phase is just as important,” said Curtis, “because the go-around itself is not without risk.”

 Recommendations

The report’s authors lament that “Safe Landing Guidelines, published by the Flight Safety Foundation to address an identified gap in the ALAR Tool Kit risk-reduction tools, is not well known by operators and not documented in operations manuals.”

And yet operators know that those recommendations work when implemented properly.

“One operator who worked on this has seen a 90-percent reduction in go-around exposure,” said Curtis, speaking for the group. “And its unstable approach rate at 500 feet and deep landing (beyond the optimum touchdown zone) rate also saw significant improvement.”

Both Marshall and Curtis indicated that a study focused on business aviation pilots and go-around decision-making would be enlightening, especially considering the number of recent runway overrun accidents involving private and chartered jets.