Towered airports reverting to uncontrolled fields

FAA Air Traffic Controllers have been there for us on Christmas, in the wee hours of boring weekdays, etc. Towers are shutting down, now, one by one, as coronaplague sweeps over the nation. Las Vegas, one of the world’s busiest airports (1500 operations per day), is no longer towered (US News). Here’s the NOTAM:

SVC TWR CLSD CTC LAS VEGAS APP CLR 125.9, CTAF 119.9 OR 725-600-7015. 19 MAR 17:44 2020 UNTIL 27 MAR 07:00 2020. CREATED: 19 MAR 17:44 2020

What happens when there is no control tower? That’s actually the normal condition at most U.S. airports, but not at airports where jets arrive on IFR flight plans every few minutes. AOPA publishes a good explanation of how pilots in radio-equipped aircraft (remember that some people fly antique airplanes with no electrical systems and no radios) are trained to do this. One key is broadcasting one’s intentions on the Common Traffic Advisory Frequency (CTAF). However, it is kind of a lost art among airline pilots, accustomed to talking to ground controller, tower controller, departure controller, center controller, …, center controller, approach controller, tower controller, ground controller.

Listen to the Vegas airplanes at (“KLAS Tower (Both)” and perhaps also the ATIS to see how the tower closure is conveyed via audio). Note that the tower frequency generally reverts to a CTAF whenever the tower is closed.

Chicago Midway, 670 operations per day, is in the same situation: to hear the Southwest 737 pilots self-announcing. The NOTAM, through April 18(!).


Uncontrolled airports can be pretty busy and can handle quite a few flights as pilots separate themselves. But this depends on (1) planes being light enough not to interfere with each other via wake turbulence, and (2) aircraft not coming in and departing under instrument flight rules (IFR) in which only one plane can use the airport at a time. (The Approach controllers can’t guarantee separation if they authorize one airplane to take off and one to arrive, for example.)

[I did this exactly once during my brief airline career, flying regional jets for Delta. We were delayed for hours out of JFK (also on the potential list for a tower shutdown) by thunderstorms and the usual JFK afternoon/evening “international push”. A heavy Airbus to Europe gets priority over a regional jet to Burlington, Vermont. Currently, KBTV Tower is open 5:30 am to midnight. I don’t remember exactly when we arrived, but it was after Tower was closed and therefore we had to turn on the runway and taxiway lights ourselves (5 clicks on the microphone to activate “pilot-controlled lighting”), announce our position to other traffic (a bizjet landed shortly before we did), fly the visual approach (maneuver the plane by looking out the window), and look out for anyone else who might be on the taxiways.]

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Great time to be in the aircraft charter business?

My friends in the charter business are saying that demand is up at least 15 percent due to coronavirus paranoia (how many Americans need to be hospitalized before we say that it isn’t “paranoia,” but rather ordinary “fear”?). A private plane never looked better!

But, on the other hand, with a huge slate of activities and events being canceled, people won’t need transportation in the first place. Will we see a brief lift in charter and then a catastrophic collapse?


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Instrument flying talk at MIT on Wednesday at 7 pm

If you’re interested in instrument flying, I’m giving a talk on Wednesday (March 4) at 7 pm, MIT Room 35-225. The topic is IFR and also planning for trips over the mountains, over water, etc. Same general idea as the videos linked from our ground school. It should be comprehensible to non-pilots, but it is designed for people who have studied at least some of the VFR topics and done at least a lesson or two.

Pizza will be served by the hosts (MIT Flying Club).

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Integrate ADS-B and AIS information for safer overwater flights?

While flying between the Bahamas and Florida at 8,000′, we were mostly outside of gliding range from land. However, we were often within gliding range of a ship (but we wouldn’t have known this if we’d been flying in or over clouds). Since 2002, ships have been broadcasting their location via the Automatic identification system (AIS). Aviation caught up in 2020 with the similar ADS-B system. For safer overwater flights in light aircraft, why not combine these two? Given the AIS information, onboard avionics could plot a path that keeps the aircraft within gliding range of at least one ship whenever possible. Given the ADS-B information, augmented with a distress button (not built into the current system, sadly), a ship’s crew would know when to start a rescue effort.

What’s the best case for modern electronics and communications currently? The people in an aircraft would to make it out of the aircraft, get their hands on an EPIRB, activate the EPIRB. The centralized group of people looking at the EPIRB signal would have to find the closest ship via AIS, then succeed in contacting the ship, etc.

Would integrating AIS and ADS-B be a good idea? I can’t find anything on the Web to suggest that it has been done or contemplated.

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Have we ever gotten an explanation for why the Boeing 737 MAX needed MCAS?

Has anyone ever seen an explanation of why Boeing couldn’t simply remove MCAS from the 737 MAX and tell pilots “you have to push forward on a go-around, just as you would in a Cessna 172 or Cirrus SR22”?

From FAR 25 (certification of airliners):

§25.145   Longitudinal control.

(a) It must be possible, at any point between the trim speed prescribed in §25.103(b)(6) and stall identification (as defined in §25.201(d)), to pitch the nose downward so that the acceleration to this selected trim speed is prompt with

(1) The airplane trimmed at the trim speed prescribed in §25.103(b)(6);

(2) The landing gear extended;

(3) The wing flaps (i) retracted and (ii) extended; and

(4) Power (i) off and (ii) at maximum continuous power on the engines.

(b) With the landing gear extended, no change in trim control, or exertion of more than 50 pounds control force (representative of the maximum short term force that can be applied readily by one hand) may be required for the following maneuvers:

(1) With power off, flaps retracted, and the airplane trimmed at 1.3 VSR1, extend the flaps as rapidly as possible while maintaining the airspeed at approximately 30 percent above the reference stall speed existing at each instant throughout the maneuver.

(2) Repeat paragraph (b)(1) except initially extend the flaps and then retract them as rapidly as possible.

(3) Repeat paragraph (b)(2), except at the go-around power or thrust setting.

(4) With power off, flaps retracted, and the airplane trimmed at 1.3 VSR1, rapidly set go-around power or thrust while maintaining the same airspeed.

(5) Repeat paragraph (b)(4) except with flaps extended.

(6) With power off, flaps extended, and the airplane trimmed at 1.3 VSR1, obtain and maintain airspeeds between VSW and either 1.6 VSR1 or VFE, whichever is lower.

In other words, an airliner meets certification standards unless it takes more than 50 pounds of push-forward on a go-around. I’m sure that there is some pitch-up moment on a 737 MAX, but it is tough to believe that a gradual trim-forward from MCAS would be sufficient if, in fact, more than 50 pounds of pushing on the yoke were required in the absence of any trimming.

The B737 already had a stick shaker for any time that it was getting near a stall (reminds pilots to push forward). So it should have been less likely to get into an elevator trim stall than a flight school Cessna 172.

Why couldn’t Boeing rip out MCAS, fire any of the coders and engineers involved in its design, tell airlines to give everyone an elevator trim stall demo in every recurrent sim session, and call the 737 MAX good?

(This is such an obvious and cheap fix that surely Boeing would have tried it if would work, so I assume that some rule would be violated, but which one?)


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Boeing dispels rumors that the SLS rocket will be overpriced…

… with a $40 T-shirt celebrating the Space Launch System (SLS):

If the project comes in on budget, it will be nearly $1 billion per launch with roughly 15 percent more thrust than the 50-year-old Saturn V.

The entire program, including the Orion capsule, appears similar to Apollo and, in fact, is named “Artemis,” after Apollo’s twin sister. I asked an astronaut why NASA would do this, 60 years after Apollo. Why not just wait for Blue Origin to have their inexpensive rockets ready at roughly the same time? “It’s what they know how to do,” he responded. My mole inside the scientific side of NASA, responding to “Unless Blue Origin fails it seems as though they will be far cheaper per pound”:

That question has been the hot topic for the last two years or so. Congress keeps pushing SLS so until there is something flying that is obviously better value, SLS will keep going. It’s a jobs program that employs all the same people that Shuttle did. And NASA has a PR push about first woman on the moon for Artemis.

If taxpayers are concerned that the true cost will be more than the $1 billion/launch planned, would it make sense for Boeing to limit the shirt prices to $25? Also, if they’re going to spend $10+ billion on a new-ish rocket, shouldn’t they be able to come up with a more original name than “Space Launch System”?


  • in the early part of this century, NASA spent at least $9 billion on the Ares I and V rockets that proved to be a dead-en (NBC)
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Aviation weather reports at the time of Kobe Bryant crash

Friends have been asking me about the Sikorsky S-76 helicopter crash that killed Kobe Bryant today. says that the crash occurred on January 26 close to 10:00 am and that conditions were cloudy/foggy.

Calabasas, California is between the Burbank and Camarillo airports. Here are their respective weather reports from around that time (10:00 am California time is 18Z). Burbank was right on the edge between visual and instrument flying conditions:

KBUR 261753Z 00000KT 2 1/2SM HZ OVC011 12/09 A3016

Translation: Burbank airport, 26th of the month, 17:53 UTC (9:53 am Pacific Standard Time), wind calm, 2.5 miles of visibility (“statute miles”), haze, temperature 12C, dewpoint 9C, altimeter 30.06. The nearly adjacent Van Nuys, airport, …

KVNY 261751Z 00000KT 2 1/2SM HZ OVC013 12/09 A3016

(almost identical)

Camarillo, closer to the coast, was slightly better:

KCMA 261755Z 03003KT 4SM HZ OVC017 15/11 A3019

26th at 1755Z (9:55 am), wind from 030 (NE) at 3 knots, 4 miles of visibility, haze, overcast clouds at 1,700′.

Over the hill at the Santa Monica airport that Californians are always getting into fights about?

KSMO 261751Z 12003KT 5SM HZ OVC018 14/09 A3018

(Translation: Santa Monica airport, Jan 26 at 17:51Z (9:51 am local time), wind from the southeast (120) at 3 knots, 5 miles of visibility in haze, clouds 1,800′ above the airport, temperature 14C, dewpoint 9C, altimeter setting 30.18.)

Assuming that it was bad weather that led to this accident, the engineering question is “Why couldn’t the $10 million helicopter fly itself away from obstacles, the way that a $400 DJI drone can?”

A Sikorsky is equipped with multiple computer-readable attitude sources so that the onboard processors know whether the machine is pitched or banked. It has multiple GPS position sensors so it knows where it is. It has at least one terrain database so it knows where the obstacles are. It has autopilot servos capable of maneuvering the aircraft. Why doesn’t it have the intelligence to say “You’re about to hit something, would you like me to take over and fly away from these obstacles and park on the ramp at the Van Nuys Airtel so that we can all relax?”


The track log shows a rapid climb during the last minute of the flight, perhaps an attempt to climb away from terrain (ignore the “PM” after the time; FlightAware translated to Eastern time):

Skyvector chart for the area in question:

Note the red circle indicating a temporary flight restriction around the crash area. Also note the “5.2” above the red circle, indicating that one has to be 5,200′ above sea level in order to clear all of the obstacles in this part of the chart. (Google Earth shows that the highest terrain near the media-reported crash site of the 4200 block of Las Virgenes Rd. in Calabasas is around 1,100′)

An alternative presentation of transponder (ADS-B) data from flightradar24:

A YouTube video puts together the flight’s track with Air Traffic Control communications (presumably from The pilot reported being at 1,400′ or 1,500′ above sea level. The Burbank and Van Nuys airports are 800′ above sea level. So this was 600-700′ above the ground (low for an airplane, but within the realm of normal for a helicopter) and thus, if the cloud layer had a flat bottom and the weather reports over 1,100’+ ceilings were accurate, the helicopter should not have been in a cloud.

The pilot had held an instrument rating since 2007, though it can be difficult to maintain instrument proficiency in helicopters, which are seldom flown IFR:

He also held a flight instructor certificate, which has to be renewed every two years. He was qualified to act as an instructor for instrument flying in helicopters:


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Masters Thesis Idea: Conversational Flight Planner

In working on the slides for a flight planning section of our FAA Private Pilot Ground School at MIT (videos and slides available free online), it occurred to me that none of the fancy computer tools were as convenient or efficient as talking to a competent human.

What about a system where the input is, e.g.,”I’m thinking about going from Bedford to Washington, D.C. this weekend.” (could be entered via menus; does not have to be natural language)

The Conversational Flight Planner responds after looking at the voluminous official FAA briefing and some of the long-term weather forecast products, such as MOS:

There will be a strong wind from the north so you should consider paying up to fly into Dulles and land Runway 1R rather than deal with the crosswind at KGAI.

Looks like ice is possible on Sunday evening so you’ll need to depart Sunday at noon.

It will be below freezing overnight Saturday night so you need to arrange for a hangar or a preheater plug-in.

Interesting Master’s Thesis project for a computer science or aero/astro major?

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Aviation lectures at MIT next week

For folks who are already certificated, there are a few guest lectures in our ground school class at MIT next week that might be interesting.

  • Monday, Jan 6, 12:30: flying the Cirrus SR-22 to Europe
  • Monday, 4 pm: “Laz” Gordon talks about the F-22 flight controls (video from last year)
  • Tuesday 4 pm: Eric Zipkin, founder of Tradewind, talks about flying the Tunison Foundation DC-3 in general and across the Atlantic to Normandy for the 75th anniversary of the invasion
  • Wednesday, 10:50 am: Michael Holzwarth talks about drone regulations (yay!) and practical experience as a Hollywood drone pilot (video from last year)
  • Wednesday (Jan 8), 12:00: Oshkosh slide show (me, being Tina’s guest! video from last year)

The fun is in Room 56-114. Except for those who are taking the class for credit, all lectures are offered at a discount of $53,450 from MIT’s normal annual tuition.

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