Beginning Wednesday, the Federal Aviation Administration started running a new "staggered parallel landings" procedure at San Francisco International Airport — a partial reversal of the March safety decision that gutted the airport's arrival rate and helped turn SFO into a byword for delay this year.

The move is a quiet climbdown. In March, the FAA declared that SFO's decades-old practice of landing two planes at once on runways just 750 feet apart was too dangerous to continue, and paused it — dropping the clear-weather arrival rate from 54 flights an hour to 36. Now, under the weight of months of three-hour delays, the agency is bringing a modified version back. The fix it is selling as a safety improvement recovers only part of what it took away — and, according to ABC7 News, the FAA spokesman who called the practice dangerous could not say why it had been allowed.

San Francisco International Airport has been running on a reduced arrival diet since March, when two runways closed for construction and the FAA simultaneously paused the airport's signature move: landing two jets side by side on closely spaced parallel runways. According to ABC7 News (KGO), which reported the rollout of the new procedure, FAA spokesman Ian Gregor said in March that officials had concluded the practice — two planes touching down at the same time on runways 750 feet apart, inside congested airspace — was "too dangerous." Gregor, ABC7 reported, could not say why it had been allowed.

That decision had teeth. The clear-weather arrival rate fell from 54 flights an hour to 36 — a roughly one-third cut in how many planes SFO could accept — and the delays cascaded from there. The Dissent has been tracking the fallout for months: three-hour-plus waits that made delay the default rather than the exception, and, this month, the awkward juxtaposition of an $11 billion airport building spree unfolding even as the airport's own runway work fueled the backups.

The new procedure, which the FAA began Wednesday, is called "staggered parallel landings." Instead of two planes arriving abreast, one is kept ahead of the other on the approach — a spacing change the agency says preserves the throughput benefit of using both runways while removing the side-by-side risk it flagged in the spring. Airport officials said the change could lift arrival capacity to 42 flights per hour by the end of August, according to ABC7.

SFGATE, reporting the same development, framed it plainly: the FAA is moving to "partially roll back restrictions" and allow more landings at the airport. The operative word is partially. Even at the promised 42 arrivals an hour, SFO would still be running a dozen flights short of its pre-March clear-weather rate of 54. And the staggered configuration is conditional: ABC7 reported the airport will revert to the existing, more restrictive procedure whenever low visibility or weather sets in — which, on the fog-prone Peninsula, is not a rare event.

The reversal raises a question the agency has not answered. If simultaneous parallel landings were genuinely too dangerous to continue in March, what changed by August besides the political and logistical pressure of a delay-plagued summer? The FAA's own framing is that the new procedure is safer than the old one — one plane ahead of the other, not wingtip to wingtip. But that only returns to the gap in ABC7's account: Gregor, asked in March why the now-"dangerous" practice had been permitted, could not say, and the FAA has offered no fuller accounting since of who signed off on it or why it took a runway closure to force a review.

For travelers, the near-term math is modest but real. Six additional arrivals an hour — 36 to 42 — is the difference between a schedule that collapses under its own weight and one that has a little slack, at least in good weather. Whether that translates into shorter lines and fewer missed connections will become clear over the coming weeks, as airlines rebuild schedules around a runway system that is still, for now, operating below capacity while construction continues.