Hangar Flying => Hangar Flying => Topic started by: Reb Wallace on November 05, 2007, 07:58:03 AM
Title: night vfr
Post by: Reb Wallace on November 05, 2007, 07:58:03 AM
I wan't to set up veze for night flying. know what fars require but looking for a source for position lights and other lights already have inst lit.any info would be very helpful can post or email me. :D
Title: Re: night vfr
Post by: Jack on November 05, 2007, 09:24:08 PM
Quote from: Reb Wallace
I wan't to set up veze for night flying. know what fars require but looking for a source for position lights and other lights already have inst lit.any info would be very helpful can post or email me. :D
I wouldn't sweat the position lights, strobes, etc. as much as being full IFR. You don't know your in clouds or IMC until you hit them. IMO, you and your aircraft need to be current in IMC before any night flying.
Jack
Title: night flying
Post by: GlennBob on November 05, 2007, 11:55:31 PM
Well,
I guess that's one pilots opinion. I had quite a bit of VFR night flying before I ever got my IFR rating. It's doubtless safer, . .but far from required. Many nights are clearer than the days because of the cooling. Flights are much smoother and of course performance is enhanced because of more dense air mass. IFR is great, but far from required for night flight.
Clouds can sometimes sneak up on you. I remember one time when the lights below dissapeared. Then I knew I had to decend and they reappeared. This was very infrequent. Most times you can see the clouds, or see that you can't see and that means clouds. Best to be up on the weather, but I would not for a minute forsake night VFR for lack of an IFR rating. And I am IFR rated.
Glennbob
Title: night vfr
Post by: Drew on November 06, 2007, 06:09:15 AM
Use these---you will be very happy...
http://www.airplanegear.com/skybright.htm
Title: night vfr
Post by: Dave in Eugene on November 06, 2007, 05:46:07 PM
I was told once:
check list for engine out at night...
1) Turn on your landing light. 2) If you don't like what you see,...turn off the landing light...
Also told that if you lose and engine during the day your have a 90% chance of walking away...during the night make that 10%....
What do you guys think fo flying at night?
Dave
Title: night vfr
Post by: Reb Wallace on November 06, 2007, 06:26:45 PM
in my travels when the daylight is longer i have no problem with time factors but when the days are shorter i like to get a jump on sunup and so just want to stay legal fo takeoff before sunup and coming back just after sundown and guess it wouldn't hurt to be seen better in daylight since everyone has a hard time seeing the eze around my home base. thanks for all the helpful info, will try airplane gear. :D the rebel
Title: Night VFR
Post by: Barney on November 06, 2007, 06:34:38 PM
Both my VEZE & RV-3 are equipped for night & IFR; however my personal unbreakable rule for myself is: NO NIGHT SINGLE ENGINE, and NO SINGLE ENGINE IFR, having had multiple engine failures in many types of aircraft, and not the nine lives of a cat.
Title: night vfr
Post by: allen on November 06, 2007, 08:34:43 PM
In the military we were taught the value of risk analysis. Some people are uncomfortable driving a car on the freeway. Others are comfortable driving their motorcycle at night on a rain soaked LA freeway. It comes down to how much risk you are comfortable with.
In the end it entirely depends on the pilot. We all should have our personal minimums and should fastidiously stick to those minimums. Recognize that the odds of an engine out off field landing in a plastic airplane are certainly not in your favor. However, how common are engine out emergencies. Are you willing to accept those odds? Are you willing to accept those odds with a loved one on board? Your child?
Determine your own comfort level. Then set your own minimums and stick to them. Hoover is comfortable barrel rolling a Commander while pouring a drink. I doubt other pilots, my self included, would be comfortable with that level of risk. But for him, it’s well within his comfort level.
Personally I cannot see a down side to equipping your plane with lights. As you said we are very hard to see as it is. This places almost the entire burden of collision avoidance on us. I would want to get the odds in my favor and if lights do the trick, then by all means do it. A good friend of mine was killed in a freak midair collision off of Malibu a few years ago so this is a near a dear topic for me.
My vote is put on the lights. The ones Drew linked to are the ones I had considered, but the plane I ultimately bought already had AC lights installed. For me, VFR night equipped was a mandatory requirement.
Title: night vfr
Post by: Drew on November 07, 2007, 02:06:54 AM
At least powerful strobes are a must just to be seen. Position lights are good for those occasions that you may be butting up next to a pinky recovery.
For the most part (civilian aviation), I don't fly at night. I make all my plans to fly during the day----and stick to it. That is a risk factor that I can directly control.
I do fly IFR----but I keep it to simple IFR. The kind where the FARs say you can't take off or land----but right after takeoff, you are in the clear. Or if I know that I will be hard IFR for takeoff, will be out of in in half an hour or so, and then have a nice VFR landing. Whatever the case is, I am pretty choosy about the IFR I fly in. I also don't like flying in the rain---I avoid as much as possible.
My scariest time IFR (in my Cozy----and before I lived by the above "rules") is when I was flying west through a cold front (stupid) to Chicago. Flew into a wall of rain---not too bumpy. And of course, EZs leak. I remember saying to myself that I hope my all electric cockpit holds up to all this water. Then poof---my engine monitor craps out---this isn't good---what's next? I kept bouncing between flight service and my center freq trying to figure out where the dry spots were. Each call to center was confirming more and more cells popping up around me. Finally I told center that I was going to divert to the nearest airport---they told me that the nearest was Parkersburg. I was getting vectors for the approach when they said there was a storm cell over the IAF. I told them---so give me the approach in the other direction----they said there was a storm cell over that one too. Ok---how about the field? No storm cell over the field. I asked for vectors to the field and minimum vectoring altitude---and that if I could not find a hole, I would shoot backwards up the approach corridor and reshoot the approach. All was good----found the hole. Landed in some light rain with clouds all around me. Wife and daughter went to the terminal as I buttoned up the plane. Then some "crazy guy" came speeding towards my plane in his pickup truck. He says "Get in!!" I say "Why?" He point to the mountainrange that just disappeared----I complied. He raced me to the terminal just as the big rain started. Couldn't see more than 2 ft outside of the terminal.
The big point is---I fly easy IFR---no reason to do "crazy stuff." There are way more easy IFR opportunities than not. The IFR license will let you safely not get stuck in a lot of circumstances. And the hard IFR gets me stuck rarely. In the above case, I should not have taken off that day.
Title: night vfr
Post by: Jack on November 07, 2007, 05:11:57 AM
Quote from: Drew
A
The big point is---I fly easy IFR---no reason to do "crazy stuff." There are way more easy IFR opportunities than not. The IFR license will let you safely not get stuck in a lot of circumstances. And the hard IFR gets me stuck rarely. In the above case, I should not have taken off that day.
Tis good to see a debate on night flying. I spent 12 years flying in the Navy and some carrier landings. Visual cues at night are few and far between and when your moving along at jet landing speeds the water gets close to damn fast.
The US is one of the few countries that allow non IFR pilots to fly at night. I was somewhat hammered for stating that if you fly at night, you should be capable of full IFR flying. Tis a damn good reason for that, I have been burned many times at night because you can't see clouds coming at you. Let alone some serious weather changes. In the Navy we were IFR trained almost from the start. In fast movers you need the IFR training.
Big hint about night flying. All this night flying gear we have in the air is basically just trying to change the night into day.
Sure you can buzz around your local airport if your real comfy with the weather. With an EZ flying out a couple of hundred miles doesn't take much time at all.
As for being well lit at night. I go with the big sky theory and hope for the best. On a very clear night I saw San Francisco from over 220 NM out one night. I was flying Herc inbound and it was beyond clear.
Right now am in Amsterdamn awaiting further transport to the sandpit.
Cheers;
Jack
Title: IFR / Night
Post by: GlennBob on November 08, 2007, 01:35:58 AM
The times you actually NEED IFR to get somewhere I think fall somewhere below 10%. But it's great to have that ability when necc. I also believe, if you think the weather is gonna be hard IFR, pack it in and wait. Usually it won't be that long. Those times seem to be less than 5 % of the time. So . ..for the other 95 % of flying, it's well worth it to pack it in that 5% of the time. I still very much enjoy night flying although I can't say I've done any in an EZ. Still reworking mine.
I plan to use Navs and strobes to be visible, which again, is better at night. I guess I'm one of the guys who is comfortable flying at night. I do try to minimize the risk though. Always looking for highways just in case. At night they're harder to find, but I watch for vehicle lights below. Also keep more alt. at night.
Glennbob
Title: Re: IFR / Night
Post by: Jack on November 08, 2007, 02:01:05 AM
Quote from: GlennBob
T I guess I'm one of the guys who is comfortable flying at night. I do try to minimize the risk though.
Glennbob
I am comfy flying in any weather day or night assuming the aircraft is properly equipped. When I started flying GA aircraft I had to reset my flight limitations because they weren't ready for icing of any type. You really don't want to hit any ice with an EZ. Starting with no pitot heat.
My old Quickie was a pure stay near the airport VFR machine. With the legs of a Long you can cruise across the country very easily.
Cheers;
Jack
Title: Lights and Strobes
Post by: mikeydidit98 on November 09, 2007, 06:06:19 PM
Traditional technology on lighting is expensive and a technology of the past. Look at the inexpensive 12V LED strobe systems on Ebay. Look at Xenon or LED at the same place for landing lights. Talk to your local car hop-up shop for single xenon assemblies and left-over controlers. Stick with aviation grade for switches/wiring/breakers, etc.
Good Luck
Mike
Title: Night VFR in an Experimental
Post by: Joe Person on November 09, 2007, 07:13:17 PM
Current Experimental Operating Limitations (NOTE: you'll need to look at your particular airplane's Op Lims, as they have gone through several iterations over the past 20 years...), per FAA Order 8130.2F, Part 153, states:
" 8 After completion of phase I flight testing, unless appropriately equipped for night and/or instrument flight in accordance with §91.205, this aircraft is to be operated under VFR, day only."
What this means is that for you to operate an Experimental aircraft at night, even though §91.205 is titled, "Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and equipment requirements", you still need to comply with the lighting requirements under this regulation.
The particulars of equipment necessary for Night VFR operations, per §91.205(c), are thusly:
c) Visual flight rules (night). For VFR flight at night, the following instruments and equipment are required:
(1) Instruments and equipment specified in paragraph (b) of this section.
(2) Approved position lights.
(3) An approved aviation red or aviation white anticollision light system on all U.S.-registered civil aircraft. Anticollision light systems initially installed after August 11, 1971, on aircraft for which a type certificate was issued or applied for before August 11, 1971, must at least meet the anticollision light standards of part 23, 25, 27, or 29 of this chapter, as applicable, that were in effect on August 10, 1971, except that the color may be either aviation red or aviation white. In the event of failure of any light of the anticollision light system, operations with the aircraft may be continued to a stop where repairs or replacement can be made.
(4) If the aircraft is operated for hire, one electric landing light.
(5) An adequate source of electrical energy for all installed electrical and radio equipment.
(6) One spare set of fuses, or three spare fuses of each kind required, that are accessible to the pilot in flight.
So, before you install a set of lights from Chet's Hotrod Shop on your flying Whatchamadigit, you'd better make sure you comply with §91.205(c), which is likely to entail that position and anticollision lights meet the lighting requirements given 14CFR Part 23 (for the size airplanes we fly).
My two bits,
Title: Night VFR in an Experimental
Post by: Joe Person on November 10, 2007, 08:38:30 PM
Two more bits:
When the FARs use the term, "approved", unless the term is used in conjunction with an identified person, the term means "Approved by the Administrator" (of the FAA).
Approval by the Administrator can occur if a product has FAA/PMA approval, for example. It might require additional approval is installed on an airplane, however.
If a homebuilt was equipped for Night VFR, as part of original construction, then that lighting technically becomes approved, as the issuance of the special airworthiness certificate is done by a Designated Airworthiness Representative (DAR). The DAR is a Representative of the Administrator, and thus approves as such. If the Night VFR lighting system was all homebrew, and the DAR approved the airplane thusly, the lighting is approved, even if it does not meet the color, intensity, viewing angles, etc., requirements that are associated with a Part 23 certificated aircraft.
Post-installation of Night VFR lighting (i.e. you decide to equip your Experimental with Night VFR lights after your flight test hours are flown off) would have to comply with §91.205, which requires that the anticollision lighting and the position lights be approved (Approved by the Administrator of the FAA). How does one do this with homebrew lighting?
Interesting situation. If one installed the ubiquitous Whelen tip lights (strobe, tail light and position lights), it is probably safely arguable that approved lights, meeting §91.205, are installed. If homebrew lights are installed, how is one going to demonstrate that the lights meet the "approved" criteria of §91.205? For Part 23 (type certificated) airplanes, Part 23 has a whole series of lighting requirements applicable to that category of aircraft.
I maintain that if one installs Night VFR lighting AFTER the airplane has its Experimental C of A, the only way to be in compliance with the airplane's operating linitations is to use lighting components that are approved. Otherwise, one would have to demonstrate to the Administrator (i.e. a DAR) that an homebrew lighting system meets minimum requirements (e.g. Part 23) for lighting systems.
I have a set of "homebrew" strobes I will be installing over this winter, as I like the improved visibility they yield - VariEzes are tough to spot, especially on days when light is dimmed by clouds, haze, etc. Being that I will not be operating Night VFR in my Eze, there will be no issues associated with whether or not the strobes are approved.
IMO, all Night VFR lighting should meet or exceed the same requirements given in Part 23. If ya wants to play like a "real" airplane, ya oughta be at least as good...
Title: Kighting Common Sense
Post by: mikeydidit98 on November 12, 2007, 12:42:12 PM
Joe;
Appreciate your FAA lesson. The reality of EAA flight is that 75%+ of the experimental planes do not comply strictly, whether it be on lights, CD players, Cell phones, Ipod jacks wired into the intercom system.... Lights are all over the place, and in my opinion, LEDs have made it a safer, more cost-effective world in which we fly. People can afford to make themselves actually visible out there at night... and not have to worry as much about blown bulbs.
The LEDs on my plane (your remember it N6553C... the varieze you tried to buy way back when) were approved at build, as was the antiquated strobes top (red) and bottom (white) back. The bottom one's controller went out, and will be replaced by a perfectly good "joe's hotrod.... and police car prefered supplier" LED strobe system... which cost me about $40. I may put a wag system on as well (LED set in each wing in the same compartment as the wing tip position lights) - another $60. The 2 interior 12" flex LED strips will cost me a total of $20. Add a free 6 station fuse panel from a friend and 2 additional switches - another $15 thanks to Ebay. So, I should be flying well-lit and very visible night in a couple weeks... for $75 (will add the wag later, if I do it, and will do the $45 single Xenon landing light (includes controler) this Winter as well. It just doesn't get much better than that.
BTW - 45 hours and climbing (pun intended) under my PIC on 53C. Adding lights as soon as parts arrive. Landing light door/actuator this winter. Taking out the Narco nav/com and the tach (which was made inop when EIS installed) and replacing the nav/com slot with an AI (want it for night VFR).
What are you flying these days?
Title: night vfr
Post by: Joe Person on November 12, 2007, 03:02:51 PM
Mike,
There are no regulations that pertain to iPods and other miscellany, in the Experimental world. In an Experimental, there is a whole open realm of possibility - that is part of the aspect of the Experimental category.
Lighting is a different thing. 91.205 is pretty specific, and is required per current operating limitations. If your airplane was signed off by the DAR (or FAA Inspector) with some sort of lighting system that was intended for Night VFR, you're good. Post-C/A installation, a bit different. Oh, people make post-C/A installations/changes all over the place, on Experimentals. Does not make all of them right. If one is to have a mishap/accident, and the investigation reveals that you made changes to the airplane in a manner not acceptable (i.e. under the requirements of the airplane's Operating Limitations, as well as all other governing regulations), then one can get into deep yogurt. Go read up on the Davenport accident and the fuel system changes that opened up a huge can or worms for the owner).
I have always striven for ensuring compliance with all regulations and requirements that apply to my airplane, and have been known to vocally urge that all others do as well (particulary the non-builder owners). Collectively, doing things below the table can hurt all of us. Just because it is an Experimental, that does not entail free-for-all operation, maintenance, and compliance to certain things.
I agree that new technology in lighting is the way to go, but installation of new technology lighting still has to end up being approved for VFR Night, per noted requirements & circumstances.
As for your airplane, no, I never tried to buy it, nor would I have ever. Both of my airplanes were built by me, as that was the only way for me to know that they met my standards for construction, integrity, etc., and the cost was much less.
Title: night vfr
Post by: Snappy on November 18, 2007, 11:33:35 AM
Night VFR? After a trip to Livermore CA, I delayed my return flight until the 100+F temps got down to a reasonable 90. Before leaving, I put in 10 gallons each side as insurance and headed home, but by delaying the departure time I was left with about 1 hour of night flying during the 2 hour trip. The Long was running perfectly so I was confident and enjoying the beautiful trip over the mountains, taking pictures and listening to the O320's steady beat.
Thirty miles out, 7,500msl - 3,000agl, over mountainous terrain and very dark I was decending east of Mt Shasta for LMT with scattered rain showers. I could see the lights of home between the cells when the engine stopped producing power completely. The VSI showed 1000 down and rain was rattling on the canopy. No roads, no lights under me and a poor daytime memory of what the gound looked like for a forced landing. I went through the emergency checklist mentally, circut breakers, mag check, carb heat, full throttle, mixture rich, best glide speed, aux pump, switch tanks (1/2 full each), scan instruments, nothing wrong and still going down. So, I flipped on the landing light, declared an emergency with the tower and started "looking" for a place to set down. Outside the canopy and below, it all looked black.
On the Garmin, I could see a road and headed for it but could not see any car lights or anything that I could line up on so I was going to shoot a night gps approach to a road that was invisible.
As a last resort, I did some heavy stick work and jinked the airplane abruptly in all directions hoping to get some fuel into the lines and get power back. It worked! The Lyc started popping and by playing with the throttle and mixture, I got 1500 to 1700 rpm which was enough to limp to the airport. After shutdown, I sat in the cockpit for a long time until the shaking stopped and went over the possibilities that could cause engine failure. At first I thought it was carb ice.
The next day, I checked the fuel system screens and found what looked to be very fine steel wool and some brass particles in the gascolator and carb inlet screen. I suspect I picked up some bad fuel and almost bought the farm because of it. This is something you can't plan for except to 'rock hop' from one potential forced landing area to the next while maintaining your basic heading. Tough to do at night.
My rule of NO night flying has been reinstated.
Title: night vfr
Post by: Drew on November 18, 2007, 01:48:08 PM
Good story---and one of the reasons I don't fly at night (mostly)----unless I have an ejection seat and/or more than one engine.
Title: night vfr
Post by: Jack on November 18, 2007, 05:44:16 PM
Quote from: Snappy
As a last resort, I did some heavy stick work and jinked the airplane abruptly in all directions hoping to get some fuel into the lines and get power back. It worked! The Lyc started popping and by playing with the throttle and mixture, I got 1500 to 1700 rpm which was enough to limp to the airport. After shutdown, I sat in the cockpit for a long time until the shaking stopped .
You kept trying something after you did the proper procedures. Always keep trying something till it's a smoking hole.
On the downside, better check your motor out. Besides the crap in the gas you had a high heat shutdown. An old study out found that running a tank out of fuel then switching over was harder on a motor than cooling the motor off in a high speed low power descent.
Nice story. Visual cues at night basically suck.
Jack
Title: night vfr
Post by: Bill James on November 19, 2007, 03:38:56 PM
Each year during the VariEze annual inspection process i figure out a way to have 2 or 3 A&Ps stop by for 30 minutes or so each. At least. In the course of something basic like adjusting the valves, I often learn something again, or learn something different from whatever he is actually doing. A little time and money well spent.
So i am intrigued as to indications, and what Snappy and his A&P would do to check out this motor for damage from a high heat shutdown. Thanks, Good flying-
Title: Hi heat shut down
Post by: djrise on November 19, 2007, 06:00:53 PM
I think he means a turbo-ed engine.
Title: Re: Hi heat shut down
Post by: Jack on November 20, 2007, 08:10:14 AM
Quote from: djrise
I think he means a turbo-ed engine.
Nope. The thermal shock involved running out of fuel in a cruise throttle setting is pretty high in any motor. As for checking it out, just monitor your engine and keep a closer eye on it in your future flights.
In all of the recips I have flown in a descent I always tried to keep some power up. 2800s on down to little motors.
Iraqijack
Title: thermal shock
Post by: djrise on November 20, 2007, 12:23:16 PM
Jack, Could you direct me to Lycoming, or Continental documentation about this? All I can find says. Fuel starvation is how to turn off the engine.
Title: Re: thermal shock
Post by: Jack on November 20, 2007, 09:05:22 PM
Quote from: djrise
Jack, Could you direct me to Lycoming, or Continental documentation about this? All I can find says. Fuel starvation is how to turn off the engine.
Mixture kill at idle is far different than running a tank empty at cruise. Check the NACA database or do a goggle search. The study I was referring to was covering cooling shock from a fast, idle descent and they went into thermal shock from fuel exhaustion at a cruise power setting.
Just think about it. Your at a cruise power setting, cruise speed and you run a tank dry. That's a helluva of a shock on the motor. Something you would like to avoid.
Jack
Title: night vfr
Post by: Snappy on November 22, 2007, 10:02:18 AM
Hi Guys, thanks for the nice words and you are right Jack, "Fly the thing as far into the crash as possible" (Bob Hoover). Great outcome and learning experience. I checked cylinder pressures after shut down by swinging the prop and noted slightly less compression than normal. Right or wrong, I normally flip the prop 15 blades or so to get oil into the system before startup. When it's cold, I go for 20 to 25 and will see oil pressure much quicker then if I don't flip the prop. So, after the high heat shutdown I continued to fly longer and longer until my confidence level in the fuel system/engine was back up. After 10 hours, I could feel the the pressure come back and after 25 hours, it is back to normal. A compression test is certainly in order and I'll post the pressures here after I complete it. Also, when you flip the prop regularly, you get a feeling for which cylinders are always stronger. Good time to check that alternator belt, exhaust pipes and baffles too.
Jack, I know of acrobatic pilots who fly without inverted fuel and routinely starve the engine during negative G manuvers (along with pouring oil out the breather). Although I don't think it is a good idea to take combustion temps from 1100+ to ambient air, none of these acro guys seem to think much about it. Cracked cylinder heads and warped exhaust valve stems over a period of time maybe?
Title: night vfr
Post by: Jack on November 22, 2007, 06:56:43 PM
Quote from: Snappy
Hi
Jack, I know of acrobatic pilots who fly without inverted fuel and routinely starve the engine during negative G manuvers (along with pouring oil out the breather). Although I don't think it is a good idea to take combustion temps from 1100+ to ambient air, none of these acro guys seem to think much about it. Cracked cylinder heads and warped exhaust valve stems over a period of time maybe?
What can I say. Abusing a single motor aircraft is never a good idea. EZs are made for cruising and finding that sweet RPM number that keeps it humming. When your cruising through the Rockies and other hostile terrain you hope that you have taken care of your single motor vice having abused it.
When the B-29s first came out, they were changing motors out left and right by 50 hours before they finally got a handle on the 3350s. If you want your Lycs and Conts to last 2,000 odd hours to TBO, you have to take care of it and listen to it.
One day they might have a viable replacement for aircraft motors that were basically designed 50 years ago and still keep on trucking.
Jack
Title: night vfr
Post by: Reb Wallace on November 24, 2007, 06:04:26 PM
well i got the position lights on the eze but could not get the strobes had to send them back because the original owner did not install a big enough tube through the wing to install the wire for strobes so going to put anti collision on the belly thanks again for all the useful info the rebel
Title: Strobes, . . .night flight.
Post by: GlennBob on November 28, 2007, 02:37:43 AM
Dear rebel,
Hey . . .you can still use the strobes. ( Too bad if you sent them back ). I was tallkin' to a guy at the EAA show who had the same problem. He took a long piece of electrical conduit and cut teeth in the end. Then he took each of his wings off and stood them on end. Wide end up. Then he used the conduit to "drill" a larger hole all the way down the wing to the tip. Guiding the conduit carefully, he said it came out perfectly on both wings. I think you could do it. Shouldn't be all that hard if you take your time and be careful.
Dear Mikey did it,
Where can you get a Xenon light for $40.00 complete with ballast ? I'll give you my order ! ! I wanted one but the cheapest I saw was $500.00.
The rest of you guys, . . can you imagine flying at night with infra - red vision ? Have you seen the video side by side of the Colorado landing by a fighter jet ? Left side of screen was night, right side was infra red ? Almost like day light ! ! I saw a system like this at the EAA. It cost about $7 K ! ! A lot I know, . .but maybe someday . .prices will come down. (Maybe not too). They said they didn't sell many. But . .$7K is cheap to save your life ! This would be great for those EZ's who don't like night flying. They guys also said the biggest problem was the huge temp change from take off to many thousands of feet in only a few minutes.