The May 2014 crash of a Gulfstream G-IV at our home airport, Hanscom Field, has now been thoroughly studied by the NTSB. It seems that there was a design flaw in the mechanical interlock intended to prevent advancing the thrust levers when the flight control gust lock was engaged. From the public meeting:
A mechanical interlock between the gust lock handle and the throttle levers restricts the movement of the throttle levers when the gust lock handle is in the ON position. According to Gulfstream, the interlock mechanism was intended to limit throttle lever movement to a throttle lever angle (TLA) of no greater than 6° during operation with the gust lock on. However, postaccident testing on nine in-service G-IV airplanes found that, with the gust lock handle in the ON position, the forward throttle lever movement that could be achieved on the G-IV was 3 to 4 times greater than the intended TLA of 6°.
Plenty of blame to go around on this accident, of course, but it is sad that this design flaw wasn’t caught earlier.
Phil,
How glaring was the fact that the pilots failed to disengage the thrust lock handle? Was this a checklist item they overlooked?
Um. You mean the throttle lever could go to 36 degrees and that convinced the pilots they could take off?
Mark,
It is a checklist item. It is also a check list item to check that the controls are “free and correct.” They did neither and apparently were lackadaisical pilots. When I am in the run up in my tiny little single engine I do the control check and I always think about
a. Aristotle Onassis’ kid, who was killed when he took off with the controls cross-wired.
b. Two professional test pilots who died in a business jet that was being developed when the same thing occurred.
Colin, your post gave me an idea. For each checklist item, have small photos of at least one pilot who died as a result of not completing that checklist item. I wonder if it would make any difference.
Mark: Sure, they overlooked a checklist item. That doesn’t mean you design airplanes on the assumption that humans are perfect. And in fact the FAA would not have approved the system that was in fact in place on the G-IV. The gust locks on planes that I have flown are all idiot-proof. It might be as simple as a seatbelt wrapped around the yoke (so if you put on your seatbelt, the gust lock is off). It might be a huge sign that obscures your view of the instruments until you pull out the pin to which the sign is attached. It might be a big stick that makes it tough to sit down.
When you meet your first perfect human, that would be a good time to order up a G-IV with this gust lock system!
No, they didn’t overlook a checklist item. They didn’t run their checklists at all and apparently they were in the habit of not running them. ” A review of data
from the airplane’s quick access recorder revealed that the pilots had neglected to perform complete flight control checks before 98% of their previous 175 takeoffs in the airplane”.
This is exactly the kind of thing that can get you (and a bunch of other innocent people) killed and it did. The interlock is supposed to protect you from your own idiocy but there are limits to how idiot proof you can make things when the pilots are truly negligent. They also failed to abort takeoff even after they realized the lock was on. In short they were bad, sloppy pilots and now they are dead pilots.
The Wright Brothers realized from their very first flight that they only way they were going to survive was by meticulous attention to detail and ground checks. The French who worked with the Wrights in the early days called Wilbur “Vieille Burette” because it sounded like “Wilbur Wright” but also because he spent so much time oiling every moving part in his plane with his little oil can (burette). Modern planes are much safer than the Wright Flyer so pilots can become complacent, but letting your guard down even once, let alone 175 times, can get you killed. These guys were playing Russian Roulette and you can only spin the barrel so many times before it comes up with a cartridge in the chamber. In retrospect what was surprising was not that these guys died the way that they did, but that it didn’t happen sooner. And I’m sure for this, Lewis Katz, billionaire that he was, was paying these guys top dollar.
Izzie: It is comforting to think that other people are stupid and/or careless, and therefore what happened to them cannot happen to us, but I wouldn’t put 100% faith in the quick access recorder. http://aviationweek.com/bca/update-gulfstream-iv-accident-bed says that “full control check” is “stop-to-stop motion” of all the flight controls. In other words, if the pilots moved the aileron and elevator through 90 percent of the possible range of motion that would not have counted as any kind of control check. The NTSB also interviewed a contract pilot who said “The PIC was very familiar with the airplane checklists and he did conduct a complete flight control check before each of their flights.”
I joined Comair not too long after https://en.wikipedia.org/wiki/Comair_Flight_5191 and the consensus among the pilots was that the captain, who died in that crash, was conscientious. I never heard anyone who knew that crew say “What happened to them could never happen to me.”
There was an accident airplane that left the Santa Monica airport and they tried to depart with the gust lock in place. It was a Cessna 172. The gust lock is a HUGE red metal flag held in place as a pin through the yoke. It is impossible to move the yoke with it in place, you cannot perform even the lightest control check with it there.
Apparently they missed it anyway, took off and dover directly into the golf course that Harrison Ford later visited (with more successful results).
It’s understandable that his friends did not want to insult his memory. But even his friend said “the PIC did not utilize a formal item-by-item checklist.” The checklists exist for a reason. Humans are all too fallible. Whatever they did on other occasions, they obviously didn’t do a control check on that day.
Inexperience can get you killed in an airplane, but so can a lot of experience if it leads to complacency. These pilots obviously felt very at home in that plane. They were like those guys who are lion trainers and become so comfortable with their animals that they forget what kind of beasts they are dealing with until one day they find out again the hard way.
The same thing could be said about flight 5191. I’m sure they were great guys (or are – ironically, the co-pilot was the only one to survive (but with horrible disfiguring injuries) out of 50 on board) but the NTSB said that they failed to maintain sterile cockpit. Maybe the runway markings could have been better but maybe if they had paid more attention to what they were supposed to be doing and chatted less about football, the 48 people who entrusted their lives to them would be alive.
Yes we are all human and we all could make the same mistake that got these guys killed – you only have to be wrong once. But letting sloppiness creep into your work does not help.
Now days, we have all those smart sensors in cars to alert the driver and prevent an accident. And soon car makers will add automatic emergency braking on all new vehicles [1].
Question #1: What it takes to make the check-list on airplanes standard, such that the airplane will not move until it senses the pilot has gone though them all?
Question #2: Far more people die a day in a car crash vs. airplane, why this does not make the news, or a Wiki page, as does airplanes?
[1] http://www.nhtsa.gov/About+NHTSA/Press+Releases/2015/nhtsa-iihs-commitment-on-aeb-09112015
#1 – Everything that goes on a plane is highly expensive, but technologically it would not be difficult to force the pilot to run thru a bunch of screens before it would let you fly – if Amazon can do this before you can order a pair of socks, so can a plane. Or to do the checklist over the radio with someone on the ground. But instead of trying to make planes more idiot proof, couldn’t we just ask pilots to do their job? If the PIC doesn’t feel like running a formal checklist, the co-pilot should be trained to insist and to refuse to fly until it is done. These two pilots knew each other too well – it would have better if they had a more arm length professional relationship – then they would both still be alive along with their passengers.
#2 Plane crashes either (1) involve more people than the typical car crash or (2) involve prominent people or (3) happen in some spectacular way (or sometimes all 3) and (4) happen less often – all of which makes each one more newsworthy. But usually if it is a small plane with only the pilot on board (and he is not well known), it doesn’t get much more attention than a car crash.
“the PIC did not utilize a formal item-by-item checklist.” could mean the distinction between a “do-list” and a “check-list”. Especially for the longer/on-the-ground lists it is common for the actions to be done in a flow and the results checked via looking at the checklist (as distinct from some in-flight checklists that are short and where each item is read aloud and then done as it is read).
It is doubtful that a pilot rose to the Gulfstream level without being at least moderately devoted to checklists. The chance of both pilots simply ignoring the checklists is even smaller.
[Actually this accident shows just how disciplined Gulfstream pilots are about checklists, I think. Despite the defective design (gust lock/thrust lever interlock) being out there for more than 20 years this was the first crash.]
The NTSB report indicated that there were at least 6 points in the checklist where the pilots should have detected that the gust lock was on and/or that the flight controls were not free before they reached takeoff speeds, so it’s not that surprising that other accidents have not occurred. Human nature being what it is, these guys were probably not the 1st to make that mistake on a Gulfstream but they were apparently the 1st to make it past all 6 checklist points without noticing.
When you read the black box transcripts from these kind of tragic flights you want to be able to shout out to the pilots. Sometimes they do or say things that ALMOST save them from tragedy but they never put 2 and 2 together until it’s too late. On Comair 5191, the co-pilot said something like, “Gee, it’s funny that there are no runway lights…..”
http://media.bizj.us/view/img/6928202/gulfstream-2.pdf