Since small aircraft are generally inferior to a 2009 Honda Accord as a transportation tool, it is worth celebrating the situations in which it make sense to fly. The Sebring, Florida race track is actually built on part of what was once a vast military airport and is now a medium-sized civilian airport. Therefore, if you are landing on Runway 1 you’ll see the race before even getting out of the plane. You’ll hear the race as soon as you’re on the ramp (remember to pack earplugs, though they also sell them at the race). After walking through the beautiful modern GA terminal you’re a 20-minute walk from the event entrance, but the kind folks at the airport run a shuttle so you’ll be there almost immediately.
The true fans, either of beer or racing, show up on Wednesday and camp:
Imagine Burning Man with no philosophy…
Here are a Corvette and Lamborghini in 1st and 2nd place (within their class) after about 2 hours. They ultimately finished in the same positions. General Motors (Cadillac) also won all three top spots in the fastest “DPi” class.
A Ferrari appears to chase a McLaren (but they’re actually in different classes):
There is a modest midway of manufacturers’ booths and food. You can develop some new respect for your neighbor with the Hyundai Elantra:
Feel better about your job… there is an actual human zipped into this outfit in the 90-degree Florida sunshine:
Although there don’t seem to have been any drivers who identified as “female”, there apparently was a competition that may have featured some who identified as “women”:
(With the kids in tow, I was unable to stay for this important event and therefore cannot supply photos.)
Chevy’s contestants in the mechanical beauty contest… a flat-plane crank engine and a cutaway Z06 Corvette:
If you’re coming down from Maskachusetts or New York and are anxious to fit in, you might want to take the Hillary, Biden/Harris, Black Lives Matter, #StopAsianHate, and “In this plane we believe…” stickers off the Bonanza.
See you there in March 2023! (the kids are already preparing!)
Friends have been asking about China Eastern Airlines Flight 5735, the Boeing 737 (non-MAX) that departed Kunming and crashed nose-down near Wuzhou yesterday.
Without the flight data recorder it will be tough to determine what happened, but what I’ve been telling friends is that there are a variety of ways that an airplane can end up in an uncontrollable nose-down attitude.
In a conventional airplane, the wings lift up from just behind the center of gravity (CG) and the tail pushes down. If the horizontal stabilizer, which looks like a small wing near the tail, were to break off in flight, for example, thus resulting in a “no tail” situation, the airplane would nose-dive because the wings are lifting from behind the CG. See the following force diagram (source):
There is a substantial amount of overdesign in an aircraft and thus extreme maneuvers may result in a component getting stressed or cracked, but it is almost impossible for the horizontal stabilizer to come off. In the comments section below, a reader highlighted Japan Air Lines Flight 123, a Boeing 747 whose tail, and, more seriously, hydraulic systems, were damaged by the failure of a 7-year-old patch to the pressure vessel.
Is it possible to lose the downforce from the tail without parts of the tail becoming detached? Yes. This can happen due to ice accumulation (see NASA videos below). It seems unlikely that the accident Boeing got into severe icing at 29,000′ (where the steep descent began), however, because the air at that altitude is extremely cold and simply cannot hold much moisture. For the tail to stall while the wings were still lifting powerfully would likely require an unusual failure of the pneumatics, which take hot compressed air from the engines to melt ice off the wing and tail surfaces leading edges.
The horizontal stabilizer’s angle relative to the fuselage can be adjusted via the airplane’s trim mechanism. The runaway-trim-by-design is what brought down the Boeing 737 Max airplanes, but runaway trim can also occur in the non-Max 737, as in other planes. There are a variety of safeguards intended to prevent runaway trim (except in the Max where the computer actually held its finger on the “trim down” button in response to absurd data from a failed sensor), but if those safeguards fail somehow and the airplane is trimmed full nose down it might not be possible to recover.
An easy-to-understand cause of a nosedive is movement of the standard flight control surfaces, in particular, the elevator (just behind the horizontal stabilizer). This can be seen at airshows, e.g., in this video of Mike Goulian at Sun ‘n Fun (I’ll be there this year on Saturday and Sunday if you want to meet). Of course, Goulian pulls out of the dive by pulling back on the stick as he gets closer to the ground. If the elevator was stuck in the “stick forward” position does that mean that the pilots of the accident Boeing had the stick full forward? (i.e., the pilot suicide theory) No. Unlike in a lightweight family airplane, the flight control surfaces of a heavy jet are not directly connected to the pilots’ yokes/control columns. No human is strong enough to overcome the air loads of the wind rushing over the control surfaces. What drives the flight controls is 3,000 psi of hydraulic pressure generated by engine-driven and electric pumps (source):
How do the pilots of a heavy jet (or “pilot” if one is in the restroom) move a flight control surface then? Ignoring the modern fly-by-wire systems of the Airbuses, the standard technique is a cable that goes from the control column to a power control unit (PCU) next to the aileron, elevator, or rudder. The PCU uses the position of the cable to modulate the application of hydraulic pressure and it is the hydraulic pump that actually moves the surface. (more) Like everything else in aviation, these PCUs are almost perfectly reliable, but if one were to fail/stick it could lead to an impossible-to-control airplane. Here’s an NTSB report regarding an elevator PCU that got stuck in 2009:
On June 14, 2009, a Boeing 737-400, registration number TC-TLA, operated as Tailwind Airlines flight OHY036, experienced an uncommanded pitch-up event at 20 feet above the ground during approach to Diyarbakir Airport (DIY), Turkey. The flight crew performed a go-around maneuver and controlled the airplane’s pitch with significant column force, full nose-down stabilizer trim, and thrust. During the second approach, the flight crew controlled the airplane and landed by inputting very forceful control column inputs to maintain pitch control. Both crewmembers sustained injuries during the go-around maneuver; none of the 159 passengers or cabin crewmembers reported injuries. The airplane was undamaged during the scheduled commercial passenger flight.
An investigation found that the incident was caused by an uncommanded elevator deflection as a result of a left elevator power control unit (PCU) jam due to foreign object debris (FOD). The FOD was a metal roller element (about 0.2 inches long and 0.14 inches in diameter) from an elevator bearing. During its investigation of this incident, the NTSB identified safety issues relating to the protection of the elevator PCU input arm assembly, design of the 737 elevator control system, guidance and training for 737 flight crews on a jammed elevator control system, and upset recovery training.
See also this Wikipedia page on problems with B737 rudder and B747 elevator control due to PCU malfunctions.
So that’s everything that I know, which is to say… almost nothing relevant or helpful, unfortunately, just like everyone else on Planet Earth until and unless the flight data recorder and, perhaps, cockpit voice recorder, are recovered.
More on tailplane icing can be found in these NASA videos…
The mobile data/voice network in the United States is spotty (in fact, there are plenty of places near our house in flat thickly-settled Jupiter, Florida where it is impossible to get data service from Verizon Wireless). This leads to occasional tragedies such as the family that died on a Northern California hiking trial last summer. For aviation and boating enthusiasts, the chance of being out of cellphone coverage in the event of a serious problem is rather high. Consequently, it makes sense to carry a Personal Locator Beacon. These are about the size of a mobile phone, but can summon rescue from anywhere with a clear view of the sky via a 406 MHz signal to a satellite network. They cost $250-400 typically.
The batteries expire after 6 years and by then it might make sense to get an upgraded version rather than send the old one back for replacement batteries and re-waterproofing.
My choice this year, which I’m definitely hoping never to use during flights over the Everglades, to the Keys, and out to the Caribbean, is the ACR PLB 425 ResQLink View. If you want to buy it straight from ACR, use “10OFFACR” to get a 10 percent discount (they sent me the code after I bought mine direct from them in order to be sure of getting the freshest battery and therefore longest life). This one is basically the same as previous ACR units, which are kind of a standard due to inherent buoyancy while being reasonably compact, but it has a small display that explains what the device is doing, e.g., “GPS Acquiring” and “406 Sent!”. The device also has a built-in strobe to help the Coast Guard find you at night in your Survival Products raft (Switlik would be better, but their rafts are too heavy and bulky for four-seat airplanes).
I hope this blog post inspires at least one reader to check the battery expiration date on his/her/zir/their PLB. If so, I will have potentially saved at least one life and therefore this post can be considered as effective as a mask order for 333 million Americans.
(There is a $50/year subscription service where testing the PLB results in some email and text messages being sent out. Potentially useful for peace of mind before heading out over the Caribbean, but the rescue process is the same if you don’t pay for the subscription.)
Related:
About the same price to buy, but $180 per year to maintain, the Garmin InReach lets you communicate via the Iridium satellites. (I don’t think this a substitute for a PLB because it requires charging and everything that can be discharged when you need it will be discharged when you need it.)
Today was supposedly the day that the East Hampton airport (KHTO) reopened as a private-only facility. More or less everything there was paid for with federal funds (raised by taxes on aviation fuel, not from the general treasury), but enough years ago that the town was free to wall it off from the public. (See “‘MEMBERS ONLY’: EAST HAMPTON AIRPORT MOVES TO PRIVATE USE” (AOPA))
It isn’t cheap to pave runways, so presumably the airport will be business-as-usual for Wall Streeters’ Gulfstreams (subject to big fees even when it was an ordinary public use airport). For peasants renting Cessnas and Pipers from regional flight schools, however, it may be another story…
From September 2020:
The FBO’s Web page suggests that the scheme is going forward, but with closure on May 17 and reopening on May 19.
Related:
“FAA ‘furious’ over East Hampton Airport’s privatization scheme” (New York Post): “East Hampton politicians’ scheme to close and then immediately reopen the town airport — and collect $10 million in surplus funds in the process — hit turbulence Wednesday” (i.e., it may be that enough Gulfstreams had landed over the years for the airport to accumulate $10 million in profit on the federally funded runways)
Friends have been asking me to explain the recent Robinson R44 autorotation off Miami Beach.
The incident, caught on surveillance camera:
If it isn’t an emergency and your machine happens to be equipped with fixed or pop-out floats and you’re practicing, it looks like the following video (throttle is rolled to idle to simulate engine failure and, due to a sprag clutch, the engine isn’t helping to maintain rotor speed).
Here’s one to a hard surface (cheating a little with a slide-reducing headwind that you can hear in the microphone):
Let’s assume that there was an engine failure in the Miami crash, which could be due to a mechanical problem, to running out of fuel, to someone pulling the mixture control inadvertently or turning off the magnetos (I always hate to see keychains on aircraft keys or, for that matter, ignition keys to begin with (jets don’t have them so you can’t turn off a jet with your knee)), etc. In that case, since we see that the rotor blades are spinning, the Miami pilot reacted correctly by lowering collective pitch and, probably, pulling back a little on the cyclic. This preserves rotor speed and enables the blades to windmill as the helicopter descends. The potential energy from being up in the air turns into a source of power to keep the blades turning, but that power can’t be used if the blades are at a steep angle of attack compared to the new relative wind (coming up from the ground).
The airspeed also looks pretty good. It is supposed to be 70 knots in an R44 (POH), but 60 knots is also sufficient for a reasonable flare and landing. What seems to have been missing in the Miami crash is the cyclic flare at the bottom. This maneuver, not that different from flaring a fixed-wing airplane on landing, turns the kinetic energy of the forward airspeed into a climb that cancels out the descent from the glide so that the net vertical speed is close to 0.
(At the end of the flare, if you want to get everything perfect and not damage the tail, you stick forward to level the skids and finally pull the collective to use the energy of blade rotation to cushion the fall from 5′ to the ground.)
Why wouldn’t the pilot flare? One thing that we tell people in training is to begin their flare at “treetop height”. This is tough to put into practice when there aren’t any good vertical references. Even experienced seaplane pilots have a tough time judging height above the water when the water is smooth (“glassy”). One can see from the top video, when witnesses are being interviewed, that there wasn’t a lot of wave action. Aside from the difficulty of judging height above smooth water there is, of course, the difference between training and the real world of surprise and shock that things aren’t going as planned.
Fortunately, nobody was killed in the Miami crash. Counterintuitively, the injuries might have been less severe if the helicopter had contacted pavement. That’s because the skids are designed to absorb much of the downward energy of a crash, but they can’t do this job when the machine smacks down in water. In order to meet FAA and EASA certification standards, the seats themselves also have to absorb downward energy by crushing and that, presumably, is what saved the occupants from being killed by the impact that we observe on the video.
It will be interesting to see what the NTSB can learn…
A senator introduced a bill for consideration by the Maskachusetts State Senate that would impose a 6.25% sales tax on new and used aircraft, currently tax-exempt in MA so as to compete with neighboring NH, ME, CT, and RI. (CT makes aircraft exempt for rich people buying machines that weigh over 6,000 lbs.; peasants buying little Cessnas, Cirruses, and Pipers must pay.) It doesn’t surprise me that a state senator would be excited to collect $5+ million in tax on a new Gulfstream G800, but of course the obvious response for the Gulfstream G800 buyer is to base the aircraft in nearby NH, thereby moving jobs out of MA. The pilots and mechanic will live in New Hampshire and the plane will zip down to Hanscom Field (KBED) or Nantucket (KACK) to pick up the rich MA resident or executives at a company based in MA and then proceed to whatever the desired destination might be. The $5+ million in tax is never collected and Massachusetts misses out on payroll and income taxes for the crew, real estate taxes for the hangar, construction jobs for building the hangar, etc.
What is surprising? The senator sponsoring this bill is Mike Barrett, whose district includes Hanscom Field, the busiest general aviation airport in New England, and all of the towns surrounding Hanscom (i.e., where pilots, mechanics, and other airport workers are likely to live). In other words, Mx. Barrett has launched a direct attack on the economic prosperity of his/her/zir/their own district.
You can see Hanscom Field at the intersection of Lexington, Lincoln, Concord, and Bedford, below.
It would make sense to me if a senator from a district that didn’t include a busy general aviation airport had sponsored such a bill, but in what other state could a politician be secure enough to directly attack the jobs of his/her/zir/their own constituents?
Speaking of state taxes, I was chatting with a friend of a friend who escaped what he considered to be the disorder and crime of Los Angeles for a new home outside of California. I remarked that I was shocked that he had chosen to live in a state that imposed a state income tax. Why not move to Florida, Texas, Tennessee, South Dakota, or one of other states without an income tax? The successful entrepreneur looked at me with pity. “All of my money is in LLCs and trusts,” he explained. “I don’t have any income subject to state income tax except for my direct salary. Everything that I spend comes from loans from one of my trusts. I borrow money from myself.”
For folks who’ve been beguiled by press releases from Otto Aviation, the Piaggio Avanti is a reminder that most of the great ideas in aerodynamics were implemented in the 1980s. The Piaggio designers threw out the rulebook on what an executive turboprop should look like and came up with a three-wing plane that goes 100 knots faster and 10,000′ higher using the same engines as a (two-wing) King Air.
The folks behind Piaggio have long claimed that the Avanti is exceptionally quiet inside, throwing out a 68 dBA number that never seemed credible.
A friend owns a 1992 Piaggio and graciously took me up to 17,500′ to make some measurements. Note that the company claims that the latest Evo model, which has a more advanced Hartzell propeller shape, is actually “20%” quieter. My friend says that a 2008 Piaggio that he flew was noticeably quieter than his 1992 model, so there may actually be three levels of Piaggio Avanti interior noise and the numbers below are the worst that one will ever see.
At Pilatus PC-12 speeds, i.e., 289 knots (222 indicated), sound at the pilots’ ears was about 72 dBA and up to 76 dBA in the passenger cabin (closer to the props spinning on the back of the main wings; closer to the door that whistles a bit (there is a trick to sealing it with a cloth that we didn’t apply for this short flight)).
At 311 knots (240 indicated), cabin noise was 1-2 dBA higher.
The owner says that the plane is noticeably quieter at its normal long-distance cruising altitudes so it is possible that the 68 dBA number is real at FL410! (He’s usually at FL370 and 370 true on 580 lbs/hour; against a headwind (and there is always a headwind because G*d hates pilots!), this is less fuel per mile than a single-engine PC-12.)
Should we all be envious of Piaggio Avanti owners? The plane is more complex to operate than the newest twin-engine turbojets that are certified for single pilots. There are switches to turn on the bleed air, for example, that typically should be thrown just before taking the runway (you’re probably taxiing with a tailwind and the result of leaving the bleeds on is some exhaust smell in the cabin). The steering has two modes, controlled by a switch on the yoke, and one is used for taxi while the other is used once 65 knots is reached on the takeoff roll. There is an autofeather mechanism that will reduce drag from a dead engine and it needs to be verified operational. Speeds are terrifying from a Pilatus PC-12 or even a Cessna Mustang pilot’s perspective. Rotate at 110 knots. Vmc is 100 knots (you can’t fly slower than this with one engine at full power and the other dead with prop feathered), final approach speed is 120-125 knots. The plane slows down very effectively with beta (twisting the prop blades to get some reverse thrust) and therefore a 5,000′ runway is plenty, but it will never compete with a Pilatus or King Air for short field performance. The Piaggio is also the wrong machine for grass, dirt, and loose gravel runways (see Burning Man for turboprop pilots for what a PC-12 can easily do if the Bay Area heroes are ever brave enough to gather again).
My friend says that the cabin is bigger than the PC-12’s (see diagrams below), but it felt smaller to me. Maybe it is the lack of a flat floor. Certainly you’ll never appreciate the genius of the Cirrus Vision Jet designers in making the pilot seats slide back 4′ until you’ve tried to get in and out of a Piaggio front seat. The pedestal extends all the way back to the seatbacks. Unless you’re a 5’2″ tall Italian yoga instructor, I’m not sure how it can be safe to get in and out during flight (without knocking a lever or switch). There is a bathroom all the way in the back, but it is not externally serviced (i.e., the owner-pilot of the $8+ million new Piaggio Avanti Evo will end up carrying a bucket out of the plane…).
The ice protection system is far better than on most newer planes. There is an automatic ice sensor that turns on the boots that protect the engine inlets. The main wing is heated via bleed air. The front wing is electrically heated. The tail is left alone and somehow the plane passed all of the certification tests and also has worked well in the real world (the Italian military operates some with more than 15,000 flights hours). (The HondaJet has a sensor-activated anti-ice system; most airplanes rely on pilots to use their eyes to notice ice building up and then set switches correctly.)
The pressure differential is 9 psi, enabling a sea level cabin up to 24,000′ and 6,600′ cabin altitude at FL410. Compare to 5.75 psi on the PC-12 and a cabin altitude of 10,000′ when the plane is at its service ceiling of FL300.
The older planes can be converted to dual Garmin G600TXi for primary flight display, but, due to the small number of eligible planes out there, there is no likelihood of Garmin certifying its modern engine instruments and GFC 600 autopilot. Below is my friend’s panel. Note the tall stack of warning lights right next to the tall stack of round dials for engine indications and remember that behind each warning light is a system that could suffer an intermittent failure that is challenging to troubleshoot. The old Collins autopilot is in the top center of the panel and the autopilot mode is currently indicated only on the lights above the switches (i.e., not on the PFD).
It would be interesting to see what could be done by upgrading the airplane with the latest GE turboprop (more fuel efficient and FADEC) and a lot more automation, e.g., changing the steering mode automatically, descending automatically in the event of depressurization (the latest planes with Garmin flight decks can do this), land itself if the old/rich guy in front croaks (trophy wife remains in middle seat and has reactivated her Tinder subscription before the flaps and gear are down), etc. If the number of switches and dials could be reduced to what you see in a Cirrus Vision Jet, and the service and support could be more like what the rest of the Jet A-powered world is used to, the Piaggio Avanti would live up to its revolutionary promise.
Some photos from our lunch-time excursion and the POH:
How does the above cabin cross-section compare to the PC-12?
If we assume 2.9′ as the mean radius of the Piaggio, that’s a cross-sectional area of 26.4 square feet. If we multiply the above numbers for the PC-12, we get roughly 24.2 square feet.
The PC-12 does seem to be longer in the back, 16’11” from the front of the passenger door to the rear of the cargo area. On the third hand, the Piaggio has a heated, but not pressurized, 67″-long baggage area behind the cabin.
One of the knocks against the mostly-pretty-awesome Vision Jet from Cirrus is high levels of interior noise. The fuselage is composite rather than aluminum and this is typically a recipe for high levels of cabin noise. Sticking the engine directly over the heads of the back seat passengers also doesn’t help.
I recently had the chance to make some measurements in an SF50-G2 using a mid-grade sound level meter.
At FL200 (20,000′) and 301 knots true airspeed (219 indicated), cabin noise was 81-85 dBA depending on the position within the cabin and, especially, whether measured at the inboard or outboard ear. Closer to the fuselage, the sound was quite a bit louder.
At FL310 and 310 knots true airspeed (190 indicated), cabin noise was 80-82 dBA.
For reference, the Pilatus PC-12 turboprop measures 83-90 dBA inside. Small business jets and the Piaggio Avanti turboprop are in the 70s. The elites enjoy cabins in the high 60s dBA, e.g., in a Gulfstream.
Because the Vision Jet doesn’t vibrate like a piston- or turboprop-powered plane, it is very comfortable inside, especially with noise-canceling headsets. A passenger who didn’t want to wear a headset might reasonably use an earplug only in the ear away from the center of the plane.
Here’s a better-than-usual Verizon mobile data situation in Jupiter, Florida:
Three bars of 5G yields 3/1 Mbps of data, which turns out to be not enough to browse the modern JavaScript and CSS-bloated web. (This was on Indiantown Road, which I hope will soon be renamed, a 6-lane main artery lined with busy strip malls.)
Meanwhile, the Garmin Pilot app (a flight planning tool) informs us that aircraft radar altimeters aren’t going to work because of 5G deployment:
So the 5G signals are strong enough to call aviation safety into question, but not strong enough to support denouncing Donald Trump, Joe Rogan, and Robert Malone on Facebook, the streaming of Neil Young tunes, or reading news regarding the January 6 insurrection.
Today is the day that FAR 135.160 goes into effect. This requires a radar altimeter (“radio altimeter” in the FAA’s parlance or “radalt”) for most U.S. helicopters. The device will display the number of feet the aircraft is above the ground. Every airliner that was ever crashed into a mountain had one of these. What stopped the crashes was the terrain awareness and warning system (TAWS).
Radalt was useful in the old days because it could ring a bell for the pilots when the aircraft was, e.g., 200′ above the ground on an instrument landing system approach. If neither the runway lights nor approach lights were in sight at that point it was time to add power and fly back up into the air (“missed approach”).
Even in 2014 when this rule went into effect it was unclear why it would be a good idea to stuff a radalt (cost range: $17,000 to $100,000 depending on aircraft and whether installed new or retrofitted) into a helicopter rather than GPS+database TAWS system that can say “There is a big radio tower ahead!” or “Climb because you are about to crash into the ground.”
The new rule applies even to helicopter operations that are limited to visual flight. The chance that the pilot is looking down at the instrument panel is small (10-20 percent) because the aircraft is being controlled by reference to the natural horizon. Combine that with the chance that the pilot would be looking at the radalt number and I would say that there is a near-zero chance that a pilot in a dangerous situation would ever become aware of the radalt value.
So one part of the government orders people to spend up to $100,000 on a device that has no practical value and then orders them not to use it because a different part of the government authorized transmissions that generate interference…
(What’s the practical importance of a radar altimeter failing due to 5G interference? The weather has to be pretty ugly before the radalt is essential on a modern airliner. At a typical flatland airport, the minimums for a “CAT I” ILS approach include clouds no lower than 200′ above the runway and visibility of at least 1/2 mile. If the weather is worse than this (think “fog”), there are CAT II and CAT III approaches that can be used by trained and authorized crews. These are the ones that always require a radar altimeter, which is used to inform the crew that it is time to initiate a go-around if the runway is not in sight and, for the highest level of CAT III approach, to cue the automated systems to initiate a power reduction and flare (pitch up).)
