18 Apr 2024, 06:58 [ UTC - 5; DST ]
|
Username Protected |
Message |
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 05:19 |
|
|
|
|
Joined: 03/09/13 Posts: 911 Post Likes: +449 Location: Byron Bay,NSW Australia
Aircraft: CE525,PA31
|
|
Username Protected wrote: There have been a lot of beer cans made from airplanes that used bad data. Yep and will continue to be. Paul did you have a rule of thumb for checking calculated speeds as a simple sanity check in the 74 to keep things honest? Andrew
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 06:11 |
|
|
|
|
|
Joined: 02/15/21 Posts: 2530 Post Likes: +1254
|
|
Username Protected wrote: If you can’t do the data right you will end up like this. Andrew Yes, and my point is that it would be nice to have a last-ditch way of verifying that the calculations have been carried out correctly. If you are not accelerating as expected, that would be one indication that something is amiss.
Andrew, you apparently fly a 525. In training did they ever cover the issue of how to ensure the airplane is accelerating properly?
_________________ Aviate, Navigate, Communicate, Administrate, Litigate.
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 10:22 |
|
|
|
|
|
Joined: 01/01/10 Posts: 3448 Post Likes: +2395 Location: Roseburg, Oregon
Aircraft: Citation Mustang
|
|
If you have a malfunction, you’re going to see/feel it. If you blow a tire, have an engine roll back, hit an object, you’re going to abort prior to V1. Things happen quickly. You don’t have time to sit and wonder if you’re accelerating properly. You either are or aren’t, and if you’re not, something will be talking at you.
_________________ Previous A36TN owner
Last edited on 03 Mar 2021, 15:30, edited 1 time in total.
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 12:03 |
|
|
|
|
Joined: 04/24/18 Posts: 727 Post Likes: +340 Location: NYC
Aircraft: ISP Eagle II SR22 g2
|
|
Username Protected wrote: If you can’t do the data right you will end up like this.
Andrew
Yes, and my point is that it would be nice to have a last-ditch way of verifying that the calculations have been carried out correctly. If you are not accelerating as expected, that would be one indication that something is amiss. Andrew, you apparently fly a 525. In training did they ever cover the issue of how to ensure the airplane is accelerating properly?
You seem to be carrying a concern over from the piston world into the turbine world. I don’t know how much turbine experience you have but especially on a light Jet like the 501 you will know very quickly if something is off via a light, gauge, feel etc.
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 12:07 |
|
|
|
|
Joined: 07/28/15 Posts: 65 Post Likes: +41
Aircraft: C510
|
|
Username Protected wrote: Yes, and my point is that it would be nice to have a last-ditch way of verifying that the calculations have been carried out correctly. If you are not accelerating as expected, that would be one indication that something is amiss.
Andrew, you apparently fly a 525. In training did they ever cover the issue of how to ensure the airplane is accelerating properly? You seem to be carrying a concern over from the piston world into the turbine world. I don’t know how much turbine experience you have but especially on a light Jet like the 501 you will know very quickly if something is off via a light, gauge, feel etc.
Agree.
Sure, it's possible in principle to have degraded performance of the engines on a tight field takeoff that leads to a late abort or takeoff but it's a bit of a corner case for most light turbines operating (usually) off runways that are much longer than truly necessary and should not be at the top of the list of concerns when there are more probable failure modes that do required careful monitoring and prompt and correct action.
I couldn't tell you exactly how long it takes to get from brake release to V1 on the Mustang but it isn't a very long time - and yet it actually varies quite a bit (in %age terms) depending on weight, temp and altitude so the calculation wouldn't be trivial and definitely not well suited to simplistic metrics like X% of Vr by Y% of the runway.
Last edited on 03 Mar 2021, 16:42, edited 1 time in total.
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 15:06 |
|
|
|
|
Joined: 03/09/13 Posts: 911 Post Likes: +449 Location: Byron Bay,NSW Australia
Aircraft: CE525,PA31
|
|
Username Protected wrote: Andrew, you apparently fly a 525. In training did they ever cover the issue of how to ensure the airplane is accelerating properly? No, but I think you are fighting shadows going down this path. Jets go or they don’t and you will sure know when they don’t. Andrew
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 22:03 |
|
|
|
|
|
Joined: 03/28/17 Posts: 6677 Post Likes: +8017 Location: N. California
Aircraft: C-182
|
|
Username Protected wrote: There have been a lot of beer cans made from airplanes that used bad data. Yep and will continue to be. Paul did you have a rule of thumb for checking calculated speeds as a simple sanity check in the 74 to keep things honest? Andrew
Andrew,
Good question to ask. Most pilots who have a lot of time in a particular type develop "resonableness checks" which could be looking at the flight plan fuel to see if it was in line with known typical fuel burns, or knowing when it's time to climb based on weights where a computer flight might have you climbing too early and burning a lot fuel to stay up there, or data-derived bug settings to see if they are close to what we know they should be from experience.
But for takeoffs we were almost at or at the weight limits often. In those cases all 3 of us would check the takeoff data, and check the data on the computer weight and balance, and check to make sure that the existing airport and runway conditions are what the data was keyed to. They planned it so close sometimes that a 1 degree increase in temperature over what was planned would keep us from taking off. As pilots on the heavy weight takeoffs we were more concerned about getting it stopped in an abort than we were concerned about the airplane being able to continue the takeoff. I mentioned in another post that we got approval to reduce our calculated V1 by 8 knots giving us a little cushion in stopping distance at some expense of height at the end of the runway with an engine out, which was minimal for the 747's, but a little harder on the DC-9's.
Most runways were plenty long even for max weight landings, and the ace in the hole was to use max braking which is considered emergency braking on a 747 and not used in normal landings. A loaded 747 on a dry runway will stop in about 3500 feet using max braking and reverse, but with the legacy 747's with steel brakes, a heavy weight max braking stop would often blow all the fuse plugs on the tires , ending up with 16 flat tires.
It became a little more critical with snow and ice on the runway. Short story: we were the first ones into Anchorage one morning after a snow storm, and they hadn't plowed the runways yet. The max allowable snow depth for landing is 6" if it's dry snow, and 2" if it's wet snow, with the determination made by the temperature; 32 degrees is wet snow, and 31 degrees is dry snow.
So ,10 miles out I asked the tower "what's the snow depth?" "6 inches" they said. "What's the current temperature?" I asked. "31 degrees" they said. Now I was skeptical because we know that sometimes the tower guys know what us pilots need and try to "help us out." It would have been a divert if the snow was any deeper or one degree warmer.
I hadn't landed on deep snow before and didn't know if there was ice under it or not, and of course I didn't want to find myself sitting in the Chief Pilot's office explaining how I ran the airplane off the other end of the runway. So, I briefed the crew that we would use the full 30 degrees of flaps for the lowest ref speed, almost never used as 25 is normal, and that we would set the autobrakes to max until I could judge the deceleration then click them off with the brake pedals and go to manual braking.
So we cross the threshold on ref, on the glide slope. We touched down, full reverse, max braking in a huge cloud of snow and came to screeching halt almost before I could click off the auto brakes and stow the reversers. We stopped so short, we had to add power to get to the first turn off. We thought "well that was cool" except that the Chief Pilot was sitting in crew van watching all of this. When we got into the blocks he raced up the stairs and reamed me for excessive braking. I just ignored him, he was desk pilot.
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 03 Mar 2021, 23:50 |
|
|
|
|
Joined: 09/21/16 Posts: 149 Post Likes: +230 Location: KSYR
Aircraft: None currently
|
|
Username Protected wrote: Back in the Falcon 20 days one of the schools had a chart to calculate your time to reach a certain speed. If you had not reached that speed within the calculated time you were to abort. I do not remember what the speed was, last time I flew a 20 was 1997.
I do not remember ever seeing the same chart for any other airplane that I have flown. I’ve read that B-52s and KC-135s use takeoff acceleration time as part of their performance calculations. The time between 70 knots and S1 speed (military equivalent of V1) is calculated during preflight planning. If the time is exceeded before reaching S1 speed, the takeoff is supposed to be aborted. If there are any USAF vets lurking, please let us know if this is correct. Greg
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 04 Mar 2021, 05:00 |
|
|
|
|
Joined: 03/09/13 Posts: 911 Post Likes: +449 Location: Byron Bay,NSW Australia
Aircraft: CE525,PA31
|
|
Username Protected wrote: Andrew,
Good question to ask. Thanks for the response Paul. Really appreciate your input on this forum. It’s guys like you that we learn from. Funny my mentor pilot (my uncle) is a retired 744 guy and I swear I could be reading his advise when I read your posts. Keep them flowing sir! Thanks Andrew
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 04 Mar 2021, 10:48 |
|
|
|
|
|
Joined: 10/05/11 Posts: 9575 Post Likes: +6444 Company: Power/mation Location: Milwaukee, WI (KMKE)
Aircraft: 1963 Debonair B33
|
|
Username Protected wrote: I’ve read that B-52s and KC-135s use takeoff acceleration time as part of their performance calculations. The time between 70 knots and S1 speed (military equivalent of V1) is calculated during preflight planning. If the time is exceeded before reaching S1 speed, the takeoff is supposed to be aborted. If there are any USAF vets lurking, please let us know if this is correct.
Greg
Interesting idea - I tend to one-mississippi, two-mississippi, etc on gear retract (14v airplane) to get an idea if the motor is getting tired.
I think I'll start noting DA and seconds to 80 mph to see what it looks like.
_________________ Be Nice
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 05 Mar 2021, 18:02 |
|
|
|
|
|
Joined: 12/31/17 Posts: 937 Post Likes: +540 Location: KADS
Aircraft: C560, C340
|
|
Username Protected wrote: Back in the Falcon 20 days one of the schools had a chart to calculate your time to reach a certain speed. If you had not reached that speed within the calculated time you were to abort. I do not remember what the speed was, last time I flew a 20 was 1997.
I do not remember ever seeing the same chart for any other airplane that I have flown. I’ve read that B-52s and KC-135s use takeoff acceleration time as part of their performance calculations. The time between 70 knots and S1 speed (military equivalent of V1) is calculated during preflight planning. If the time is exceeded before reaching S1 speed, the takeoff is supposed to be aborted. If there are any USAF vets lurking, please let us know if this is correct. Greg
I looked at my old Falcon 20 stuff and it was CAE, and probably Falcon, that supplied the time from brake release to 100K. In the picture below I circled the time in seconds. This page is at gross weight. I remember departing Idaho Falls one warm day and having to do a 0 flap takeoff and our weight was limited by the tire speed. I cannot remember if the limit was 180 or 200mph but I went through a lot of charts to find out our max takeoff weight!
The CAE info on the C500 stuff that I have does not supply that time.
Attachment: Screenshot_20210305-151351_Gallery.jpg
Please login or Register for a free account via the link in the red bar above to download files.
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 05 Mar 2021, 23:09 |
|
|
|
|
Joined: 09/21/16 Posts: 149 Post Likes: +230 Location: KSYR
Aircraft: None currently
|
|
Username Protected wrote: At gross weight, 6000 feet elevation and 50F the chart says 28 seconds to get to 100K. It seamed forever to get to the 145K rotation speed. Reminds me of flying the JetStar II and 731 JetStar. With four engines, they were almost never second segment limited. Runway length was almost always the limiting factor. I remember a Las Vegas departure on a 105 degree (F) day. We were headed to HPN with every seat filled, a headwind component, and an alternate required. The flight plan called for 4:45 enroute, requiring 17K pounds of fuel. We were just 500 pounds under gross weight. No quick reference performance numbers that day. I think I reviewed every performance chart in the book! After much analysis, we met all the performance criteria, including tire speed, brake energy, and second segment climb. 12,500’ of runway were required and 12,500’ of runway were available. I swear we needed a calendar to measure the takeoff roll time... Greg
|
|
Top |
|
Username Protected
|
Post subject: Re: Citation 501sp Posted: 05 Mar 2021, 23:58 |
|
|
|
|
|
Joined: 07/24/14 Posts: 1760 Post Likes: +2217
|
|
Username Protected wrote: At gross weight, 6000 feet elevation and 50F the chart says 28 seconds to get to 100K. It seamed forever to get to the 145K rotation speed. Reminds me of flying the JetStar II and 731 JetStar. With four engines, they were almost never second segment limited. Runway length was almost always the limiting factor. I remember a Las Vegas departure on a 105 degree (F) day. We were headed to HPN with every seat filled, a headwind component, and an alternate required. The flight plan called for 4:45 enroute, requiring 17K pounds of fuel. We were just 500 pounds under gross weight. No quick reference performance numbers that day. I think I reviewed every performance chart in the book! After much analysis, we met all the performance criteria, including tire speed, brake energy, and second segment climb. 12,500’ of runway were required and 12,500’ of runway were available. I swear we needed a calendar to measure the takeoff roll time... Greg The Jetstar is one of the coolest planes ever made.
_________________ Jay
|
|
Top |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum
|
Terms of Service | Forum FAQ | Contact Us
BeechTalk, LLC is the quintessential Beechcraft Owners & Pilots Group providing a
forum for the discussion of technical, practical, and entertaining issues relating to all Beech aircraft. These include
the Bonanza (both V-tail and straight-tail models), Baron, Debonair, Duke, Twin Bonanza, King Air, Sierra, Skipper, Sport, Sundowner,
Musketeer, Travel Air, Starship, Queen Air, BeechJet, and Premier lines of airplanes, turboprops, and turbojets.
BeechTalk, LLC is not affiliated or endorsed by the Beechcraft Corporation, its subsidiaries, or affiliates.
Beechcraft™, King Air™, and Travel Air™ are the registered trademarks of the Beechcraft Corporation.
Copyright© BeechTalk, LLC 2007-2024
|
|
|
|