# Abbottabad Helicopter crash - rotors couldn't generate lift? **URL:** \ **Category:** Factual Questions\ **Created:** [May 3, 2011, 2:25pm UTC](https://boards.straightdope.com/t/abbottabad-helicopter-crash-rotors-couldnt-generate-lift/580570 "2011-05-03T14:25:43Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 5, 2011, 7:11pm UTC](https://boards.straightdope.com/t/abbottabad-helicopter-crash-rotors-couldnt-generate-lift/580570/21 "2011-05-05T19:11:04Z")
> [@Hail\_Ants](#): > > **Paging JohnnyLA!!** Hello. I’m working, and just popped over while a program is running. I’ll return later this evening or tomorrow evening, and possibly add something. But I suspect all will be answered by that time. ---
**Author:** ![Skald\_the\_Rhymer](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Skald\_the\_Rhymer](https://boards.straightdope.com/u/Skald_the_Rhymer)\ **Post date:** [May 5, 2011, 7:21pm UTC](https://boards.straightdope.com/t/abbottabad-helicopter-crash-rotors-couldnt-generate-lift/580570/22 "2011-05-05T19:21:13Z")
> [@lieu](#): > > I’m a little surprised that this issue wasn’t identified previously in the prepatory drills they ran within the ‘identical’ compound mock-up. No plan ever survives contact with the enemy. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [May 6, 2011, 4:43am UTC](https://boards.straightdope.com/t/abbottabad-helicopter-crash-rotors-couldnt-generate-lift/580570/23 "2011-05-06T04:43:02Z")
A few thoughts: I flew Robinson R22s and Schwiezer 300CBs in SoCal. I’d generally go through the Newhall Pass at about 2,400 or 2,500 feet MSL. I’d have to dig out an E6B and use a typical temperature to tell you the density altitude, but suffice it to say that 35ºC it was probably around 5,000 feet. Of course I was flying around 70 kts. and not landing, but I’m sure I would have had no trouble taking off and landing on a hot day in an underpowered helicopter. I doubt density altitude was much of a factor for a big Sikorsky. Someone mentioned quick stops. A quick stop is a maneuver a helicopter makes when there is a power failure on take-off. Basically, you’re flying a take-off profile. Then you lower the collective, reduce anti-torque, and pull back on the cyclic to reduce your forward airspeed and touch down. This has got to be my second-favourite maneuver. It’s loads of fun. You do get your tail low, and [a tail rotor strike is pretty much sub-optimal](http://www.youtube.com/watch?v=fpv7ZAMyQcc). Another way to strike your tail rotor is to come in ‘hot’ and not level out in time. A fast, steep approach to a confined area? Yeah, I can see it happening. Settling with power (vortex ring state) has already been linked upthread. (I didn’t read the link.) In the helicopters I’ve flown, this occurs at an airspeed less than 15 kts. and a rate of descent greater than 300 feet per minute. Again, I can see this happening in a fast, steep approach to a confined area. Being a confined area, remedial action may not have been possible. I don’t know if it’s mentioned in the afore-mentioned link, but adding power exacerbates the problem. And of course there’s always banging the rotor against a wall. ---
**Author:** ![Bear\_Nenno](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bear_nenno/32/3358_2.png) [@Bear\_Nenno](https://boards.straightdope.com/u/Bear_Nenno)\ **Post date:** [May 6, 2011, 6:54pm UTC](https://boards.straightdope.com/t/abbottabad-helicopter-crash-rotors-couldnt-generate-lift/580570/24 "2011-05-06T18:54:50Z")
> [@TriPolar](#): > > **Bear** , do you have a cite for this? I’m not doubting you, I’d just like to see the actual reports. **TriPolar** , I checked the Stars and Stripes article the next day at work and it wasn’t in there. I couldn’t find the article anywhere, which really started bugging me because the same article mentioned things like suggestion of “stealth” helicopters before it was mainstream, and also mentioned that none of the inteligence obtained for this mission came from water-boarding. With so much valuable information in one article, I was starting to think I imagined it! Just found it again today, though! “No shots were fired, but shortly after the team hit the ground, one of the helicopters came crashing down and rolled onto its side for reasons the government has yet to explain.” From here: > **[HuffPost - Breaking News, U.S. and World News](https://www.huffpost.com/)** > > Read the latest U.S. and world news, politics, entertainment, lifestyle and opinion pieces from HuffPost’s trusted team of journalists. [Previous page](https://boards.straightdope.com/t/abbottabad-helicopter-crash-rotors-couldnt-generate-lift/580570.md?page=1)