What is your procedure when a microburts is issued? How long must you stay on the ground before taking off?

I am asking because of the microbursts alerts issued out of Denver couple weeks ago and watching a Lynx plane takeoff on Runway 08 in the middle of the alerts.

Also to be fair, a United, SouthWest, and Frontier used Runway 08 for departure during the alerts. Everyone else on Tower freq declined to take off on Runway 08 or 17R and 17L. I was in shock as to why those 4 planes took off while multiple planes were going miss on runway 16R and 16L.

Thank you.

 

Read this for a good explanation, understand the words "potential" and "judgement" in their proper context: Lesson 5: Wind shears and Microbursts

 

I'm not with any of those carriers, but my understanding is microburst alerts are issued in reference to a specific runway. If there's no alert for your runway, you're legal and it becomes the crew's call.

 

I hate to say it but I've witnessed the same thing many times. Very unprofessional, and the company will blame the PIC for any mistake and let him/her hang in the wind if anything bad happens.

I was trying to takeoff from RNO a few months ago. Low layer of very thick fog, but it was probably very thin too. Tower was reporting Rwy 16R RVR @ 600' (below minimums), surface visibility 1/2 mile (above minimums). Sounds like a pretty strange observation, right? There is no RVR installed on the North runways, 34L or 34R so prevailing visibility applies. (Why the tower felt that this was an acceptable observation is another story. Every accident has a series of events, this could have been one of the preventable ones if there had been an incident.)

That reported observation made it "legal" to takeoff on Rwy 34L but when we taxied down to the runway for takeoff we could see only two runway edge lights. That's 400' if I'm not mistaken. Well below takeoff minimums for any commercial operation. We pulled over to the side to wait for the fog to burn off. As we sat there the visibility ranged from less than 200' (we could not see the runway lights at all) to 400', yet we saw 2 Southwest 737's and a Horizon Qprop takeoff without hesitation. We ended up waiting almost an hour for the visibility to come up to our observed minimiums.

What happens if the "reported" visibility is drastically different than the "observed" visibility? I believe observed visibility takes precedence. I think had an FAA inspector had been sitting in our cockpit observing, those pilots who took off would have been in for a tough hearing before the FAA. But hey, they took off on time and kept the company rolling. Besides, no executives were ever in any jeopardy, and that's what really counts, right?

 

The Lynx guy must have had nothing to live for after RAH took all his flying.

Sorry I kidd, couldn't resist.

 

Both Southwest and Horizon have Heads-up Guidance System guidance in their aircraft. That allows takeoff minimums of 600 RVR at many airports, and down to 300 RVR at a few (very doubtful that RNO is one of these). With HIRL, CL, RCLM, and a functioning localizer on 34L, I'm guessing they have 600 RVR minimums (anyone at Southwest or Horizon feel free to correct). It's also entirely possible with the way that visibility can fluctuate that when they moved into position they were able to see at least 600 ft.

 

To actually answer your question, there is no set time limit. Obviously you cannot takeoff or land with the advisory in affect. Once the alert has ended, you may takeoff and land, but caution should be exercised. On the ATIS, the advisory stays for 20 minutes after it's ended, I believe. However as long as the alert is no longer in affect, you can takeoff and land. Remember, lawyers write the flight manuals, not pilots.

 

lol @ Waldo!

Thank you for your responses. The Lynx plane I saw took off of Runway 8 was cleared for takeoff after numerous windshear alerts were for runway 8. (the plane was in position and hold.) After the takeoff clearance. 2 to 3 seconds later tower cancelled the takeoff and reported windshear off runway 8 of 40 knot loss on departure. Then 3-4 minutes went by and the windshear alert was cancelled by the tower controller and then the tower controller cleared the Lynx plane for takeoff.

Their must have been maybe at least 25-30 windshear alerts for runway 08, 17R, and 17L. The 4 planes that I saw took off went in the middle of the microburst alerts but yes AFTER the tower cancelled the alerts. I didn't see the point of rushing but that is just me.

Thank you jungle for the read.

 

1/4 for SWA at RNO.

 

I agree with you. It's been almost 3 years since i flew at Horizon but remember with the HUD it was 300RVR