NASA · Aviation Safety Reporting System
B737-700 First Officer reported slowing below assigned speed without clearance to avoid wake turbulence while on descent into LAX following a preceding B757.
What is ASRS?
The Aviation Safety Reporting System is NASA's voluntary, confidential, non- punitive incident-reporting system, established 1976. Pilots, controllers, dispatchers, and maintenance technicians file reports describing safety- relevant events. NASA de-identifies every report before adding it to the public database. Reports are not investigated by NASA, the FAA, or the NTSB — they represent the reporter's perspective.
Pilot narrative
Verbatim from the de-identified NASA record. First-person account by the
reporter. NASA strips identifying details (names, company, specific time);
anonymization placeholders are ZZZ,
X, Y.
We were on visual approach to Runway 25L with a landing clearance. There was a 757 in front of us that was causing some wake turbulence. The Captain, pilot flying, decided to slow from the assigned speed of 170 to 150 in order to increase separation. We had about a 3-mile spacing and the 757 was slowing early it appeared. Shortly thereafter, ATC asked if we were doing 170 and we responded “affirmative.” When they asked again, the Captain jumped on and said he was doing 150 for wake spacing. ATC implied that we had more than enough, and we landed without incident. Pilot flying slowed 20 kt. below assigned speed to avoid wake turbulence without clearance to do so. We should have asked for slower instead of just doing it. Better crew communication. We could have also gone around and tried again with a better buffer.
NASA classification — Anomalies
- Deviation - Speed
- Deviation / Discrepancy - Procedural
- Inflight Event / Encounter
NASA classification — Assessments
- Contributing Factors / Situations
- Environment - Non Weather Related · Human Factors · Procedure
- Primary Problem
- Human Factors
ASRS reports are voluntarily submitted, de-identified by NASA, and represent the reporter's perspective. The presence of reports on a topic cannot be used to infer prevalence in the National Airspace System. The authoritative source is the NASA ASRS Database Online at asrs.arc.nasa.gov ↗.