By JOAN LOWY, Associated Press
WASHINGTON (AP) — Experienced pilots say the challenges of landing at San Francisco International Airport were further complicated by the shutdown of a ground-based instrument landing system and the movement of runway thresholds prior to Saturday's crash of a Korean airliner.
The instrumental landing system, or ILS, uses radio signals to create a three-dimensional "glide slope" for planes to follow so they aren't too high or too low or too far to the right or left.
Rory Kay, a major airline pilot who flew into San Francisco the day before accident, said the ILS for the runway where the Asiana airline plane crashed was shut down. He also said the beginning of the runway was moved 300 feet to the west to accommodate construction at the airport.
- PHOTOS: Asiana Airlines Jet Crash Lands in SF
- Obama Grateful to First Responders at Jet Crash
- Experts: Boeing 777 Has 'Fantastic' Safety Record
Copyright 2013 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.