Truly, helicopters do not fly so much as thrash the air into submission.
A novel use of engine braking.
Ahem, 
Not much fun flying around the Middle East these days.
See the video in this Reddit thread for what the helicopter was actually shooting just before it went down (a bus accident)
I’ve never flown a turbine, but it sounded to me like the engine failed, followed by a low rotor RPM warning. In the event of an engine failure, the rotor system automatically disconnects from the engine. The procedure is to immediately lower the collective to preserve rotor RPM and enter autorotation.
I could not tell from the video how high the helicopter was, but:
A helicopter may be operated at less than the minimums prescribed in paragraph (b) or (c) of this section, provided each person operating the helicopter complies with any routes or altitudes specifically prescribed for helicopters by the FAA; and
I often flew at 400 feet AGL. Now have a look at a height-velocity diagram. The slower you fly, the higher you need to be to be in the envelope. In a Bell 204B (the depicted diagram), the helicopter would have to be at least 800AGL to have a chance of a safe autorotation landing from hover. I couldn’t quickly find a ‘dead man’s curve’ for an A-star, but it would show ho high they needed to be to autorotate from hover.
ETA: Low rotor RPM is bad.
It sounds like you’re saying every helicopter in the process of landing and is at 50 to 100 ft isn’t survivable if the engine quits.
Not what the chart says at all. For any given altitude, there’s a forward airspeed (or range or airspeeds) that’s safe. That’s why helicopters typically do not take off or land purely vertically.
This is also why police or news helos generally circle an incident rather than hover over it. Keeping some forward speed, even if it’s not huge, reduces the height they can safely be at and still manage a safe landing following an engine failure.
Precisely.
Part of my training included taking offs and landings in confined spaces. It was stated that the operations were outside of the envelope, and that performing them was a ‘calculated risk’. That is, you can take off and land vertically, but if you lose power, then you’re in trouble. The ‘calculation’ is that aircraft rarely lose power, and that you will be hyper-sensitive to any indication that something is wrong; plus that you’ll get back into the envelope as soon as you can clear the obstructions. Of course, the greater risk of operating in a confined area is striking your tail rotor (or main rotor).
In extremis the FO can fight as hard as he wants. Slam the throttles full forward and hold them there, etc.
It helps if the FO is bigger than the Captain. There was a lightplane accident we covered upthread where the pilot / owner was a 40-ish former NFL player and the CFI in the right seat was in his 60s and of ordinary size. Engine failed after takeoff and the forced landing turned into a stall/spin. Decent bet the CFI was unable to wrest control from a panicked muscular dude.
In general you need to force the situation to the point that you break through the other person’s tunnel vision. The Pakistan Airbus mishap cited by @JKellyMap just below your post was a failed example of that.
The FO mustered the gumption to physically override the Captain’s desire to land by raising the landing gear. Which he (presumably) thought would be a large enough cue the Captain would notice it and realize that now he had to go around. Instead, the Captain seemingly never even noticed the gear change, and continued to touchdown anyhow. Oops.
You also have to be careful about uncoordinated configuration changes. There was a recent bizjet accident that I think was covered upthread. IIRC it was late night into a reliever airport near San Diego. Old head FO, newbie Captain who’d just transitioned into the type after being hired. But otherwise an experienced bizjet driver. They get high and tight and fast trying to make a night visual approach. Once fully configured and turning a close base the FO decides to “help” by extending speedbrakes hoping to salvage the approach.
Instead, the wing promptly stalls and they half-turn spin into the ground. Spoilers are not just drag devices. They are also lift-destroying devices. And in most jets there’s some flap setting beyond which spoiler us is prohibited. Why? Because the lift disruption is so extreme the wing stalls. Oops.
The first steps of a go-around in almost any jet are nose up, add power, and reduce flaps. With nose up being the most immediately important step, to start a vector away from the ground. You’ll need power in 10-15 seconds or you’ll stall after bleeding off your airspeed cushion. Raising flaps helps climb capability, at the expense of at least at first increasing your stall speed closer to your current speed.
Somebody unilaterally raising the flaps from “landing” to “go-around” as an attempt to force a go-around is also a trap. Not as instant as speedbrakes, but until the pilot flying knows and understands what’s going on, all they see is weird airspeed limits and AOAs. Any further stupidity or ham-handedness and they’re into a stall much earlier than expected. Oops.
Probably the best thing to do is shout “My aircraft! Going around!”, whack the other pilot on the shoulder and grab all the controls. The point is to startle, not injure. And in that moment, grab the situation by the balls and get the go-around going. That was always my plan.
From reading this thread you might think, “I’m not flying ever again.” But there’s 100s of 1000s of flights every week where the aircraft/pilots never venture into the dark recesses of the flight envelope. So back into the air I go.
On September 17, 2026, a Texas Air National Guard F-16 fighter jet crashed during a routine training exercise in northern Michigan. The pilot successfully ejected from the aircraft and is in stable condition. From the ATC, wingman reported a bird strike on his lead.
on a helicopter that is close to the ground or is landing. Can the pilot reduce the blade pitch and increase the rpm’s to increase rotating mass?
I presume this is a power-failure situation? Lowering the collective (reducing the pitch) is the first thing you do in the event of a power failure… and quickly. This reduces drag, which allows the blades to spin long enough for the aircraft to drop and establish an upward airflow like a pinwheel. Now you have an inboard ‘driving region’ and an outboard ‘driven region’. The aerodynamic forces in the driving region are forward of the axis of rotation, so it provides thrust. So once you’re in autorotation, the blades will continue to spin for as long as you have altitude.
In a typical landing, with or without power, and assuming a stable approach, you set your collective just as you would set your power in a fixed-wing. [BTW, the throttle is at the end of the collective, and there is a correlator that correlates power to pitch.] At about 40 AGL, you start your flare by pulling back on the cyclic. Of course this increases drag and lift, so you lower the collective. At about 3 AGL, level your skids and come into a hover (if you have power). (This caused me much consternation in training, because I was conditioned to pull back until the wings stall as you touch down on the runway. Helicopters are different from airplanes.) When you level the skids, you’ll need to increase the pitch of the rotor blades so that you don’t hit the ground hard. Then gradually lower the collective to land. If you don’t have power, pull the collective to cushion the landing.
The problem is when you do not have the altitude, or airspeed, to successfully enter autorotation. If you refer back to the left side of the height-velocity diagram, you will run out of altitude before you can establish autorotation.
Incidentally, there is the height-velocity chart from NTSB for a Robinson R22 (.pdf file). It shows the envelope at sea level/1,370 pounds, and 7,000 feet/1,300 pounds.
I didn’t ask the question right. Can you fly at a higher rpm under power with less less blade pitch as a hedge against engine failure? It would be less fuel efficient but provide additional rotational mass when flying low.
RPM is different in helicopters. Instead of RPM, you read percentage of RPM. Here is a gauge:
In an R22, the maximum rotor RPM is 104% Exceeding maximum rotor RPM risks catastrophic failure (as in, the rotor blades depart the aircraft, which would be bad) due to excessive centrifugal (and possibly vibrational) forces. Just stay within the envelope.
Quick stops are a simulation of a power failure on take-off (post-hover). They’re incredibly fun. 
Oh… When the needles are not indicating the same percentage, they are ‘split’. This happens in a power failure when the engine RPM is zero, and the rotor RPM is (hopefully) around 102%.
A 9/11 related story
(& no, I’m not late with it, but right on time as it happened today, well the second Friday after 9/11)
9/11/2001 - 4 hijacked planes, two buildings demolished, almost 3000 murdered. In a matter of hours ALL privately owned airplanes out of the skies.
A couple of days later commercial aviation resumes but GA is still grounded.
The third weekend in Sept for the then-past 25+ years is the Adirondack Balloon Festival; hard to hold an aviation event when no GA is allowed but yet somehow they get permission to have the festival so this is some of the first GA flights to happen since the attacks. Al is going to show those @#$%& bastards, that while we may be down, we are most definitely not out! In a hastily crafted idea (only 10 days after the attacks) Al decides he wants to show the terrorists that our spirit is strong & what better way to do that than to wave the flag up high while doing what’s known as a top walk.
I had wanted to recreate it for the 20th anniversary; had permission from the festival organizers, had met a couple of times to work out all of the technical details...& then the insurance co go wind & said, not only no, but "Hell, NO!". :cry:
A video of the LA helicopter coming down: