While they can't see your indicated airspeed, controllers need you to maintain speed restrictions for aircraft separation. Here's what happened to this crew departing LAX...
First, Let's Review SIDs
You typically find departure procedures in major terminal areas, like Denver or Houston. They're only flown by aircraft on an IFR flight plan, and they're used even if the weather is clear.
Most of the charted departure procedures are published to manage traffic. They're called "Standard Instrument Departures", but you'll usually hear them called "SIDs." You can group them into three types: radar vector SIDs, pilot navigated SIDs, and RNAV SIDs.
Whenever you're assigned a SID, you must meet any published speed restrictions on the SID, regardless of whether you're given a "climb via" or "cleared via" the SID instruction.
Report: Boeing 737 Crew Departing From LAX
The following NASA ASRS report details a flight crew that exceeded a 250-knot speed published speed restriction out of LAX. It can happen to anyone, especially when this happens...
Pilot 1:
Flying LADYJ 2 RNAV Departure in VNAV, we allowed aircraft to accelerate to climb speed at 10,000 ft instead of adhering to 250 knot restriction until notified by ATC. Passing approximately 12,000 ft, SoCal notified us of the airspeed deviation. We pre-briefed the departure and were prepared to comply with the airspeed restriction.
As a technique, I will manually place 250 in the 10,000 ft climb to protect airspeed restriction or manually select Level Change, such as XXX restrictions. I failed to do so this night due to distractions and attempts to get our "push" clearance. Also, I had expanded the departure page diagram to better see the page at night which actually hid the departure airspeed restriction resulting in a 296 KIAS climb above 10,000 ft.
Pilot 2:
We were flying the LADYJ 2 RNAV Departure out of LAX. It has a speed restriction of "MAINTAIN AT OR BELOW 250 KNOTS UNLESS OTHERWISE DIRECTED BY ATC." I had the LADYJ 2 Departure displayed on my EFB but had the view expanded where the speed restriction was not in view. VNAV was selected passing 3000 ft AGL so after passing 10,000 ft MSL, the aircraft accelerated to normal climb speed. When ATC gave us a frequency change they advised us that in the future maintain 250 knots until assigned normal speed.
ATC Can't See Your Indicated Airspeed, But They Still Have A General Idea Based On Winds
When controllers sit down to take over a section of airspace, they read reports to get a general sense of the wind conditions aloft.
Let's say a published procedure has a crossing restriction of 250 knots. If every airplane is maintaining around 280 knots ground speed on their scope, the controller knows that the winds aloft are giving aircraft a 30-knot tailwind. If one airplane in the group flies across the fix at 310 knots, the controller would likely question if they've exceeded the speed restriction.
In most cases, controllers will just ask you to slow down, speed up, or remind you of the restriction. However, it's still acceptable for ATC to file a pilot deviation report on your flight if you've broken the restriction.
EFB Chart Position Matters
No matter how many briefings you do on the ground, it's easy to forget important information once you're busy in the air. That's why you reference charted SID or STAR procedures to cross-check things like speed and altitude restrictions.
You can also remember important details by using the highlighter tool on your EFB for restrictions that apply to you.
Also, be careful if you zoom in on a particular section of a chart, because you might no longer see a speed restriction or other important info on the chart.
This is exactly what happened to the crew in the NASA report. They had their chart zoomed in, obscuring the speed restriction written on the LADYJ 2 Departure.
Try to keep your chart zoomed out or in just enough so that you continue viewing all relevant crossing restrictions.
What Do You Think?
This is a mistake that can happen to any crew. What's your strategy to avoid similar mistakes? Tell us in the comments below.
Become a better pilot.
Subscribe to get the latest videos, articles, and quizzes that make you a smarter, safer pilot.
