Monday, March 30, 2009

The Better Part of Valor

I decided that the best approach today for getting from DC to Bridgeport was the train. Here's why:

The green icons are pilot reports of icing. The orange icons are pilot reports of turbulence. I concluded that it wasn't worth arguing with. Unfortunately, that means I'll be back on the train Friday. I do so look forward to the advent of consistent above-freezing temperatures aloft.

Saturday, March 28, 2009

Friday Night's Flight

As I was leaving KBDR, the TAF for DCA (issued at 1800Z) was still valid and calling for better than 6 miles visibility and scattered clouds at 3000 feet at my planned arrival time. After I got off, I zoomed out the XM Weather NEXRAD display on my Garmin 396 and saw lots of green and yellow stuff just south of DC, with the leading edge maybe 1/2-way between DC and Richmond. Since I had 2 hours of flying in front of me I figured there was a good chance that the weather would get to where I was going before me. Time to brief the approach plate.

It was VMC most of the way down. I started out at 8000 feet going over to Sparta and down to Solberg (that keeps me above the EWR arrivals) and there was a pretty good headwind at that altitude. I knew from the winds aloft forecast that the winds were quite a bit lighter at 6000 so as soon as I was handed off to Allentown Approach I asked for and got 6000. That got me about 9 more knots of ground speed.

The undercast went solid just north of Baltimore. Passing BAL headed south they took me down to 4000. That had me under the cloud layer where it was showery and maybe 3 or 4 miles flight visibility. The approach controller asked me what approach I wanted at VKX and I asked for the RNAV 6
On the way down to Nottingham VOR, Potomac Approach brought me down to 3000, then to 2000 and with each descent the visibility got a bit worse. I went through a couple of pretty enthusiastic showers where it was probably around 1-1/2 miles, and prevailing visibility in the light rain was about 2-1/2 (I estimate).

So...I clear Nottingham and the controller says, "Depart Nottingham on a 270 heading, expect the visual at VKX."


So I said, "Umm...there was some talk with the previous controller about shooting the RNAV 6 into Potomac...", and he said, "Well, there's a lot of traffic coming up from the south tonight -- maybe you can pick up the airport. If not we'll get you vectors to WOBUB." (Note: WOBUB is the IAF for the approach)."

"OK," I said, "we'll see what happens."

Needless to say, I got within 4 miles of the field at 2000 and saw NOTHIN'. So, he turns me to a 240 vector paralleling the final approach course, offset about a mile and a half to the southeast. I get abeam of WOBUB and he clears me direct, cleared for the approach. I already had the approach loaded in the GNS-530, so I just hit Direct WOBUB and away we go. But...it occurs to me that the 530 wants me to get to WOBUB and turn southwest to fly the hold-in-lieu-of-procedure-turn, and Mr. Controller may not want that. I ask, "Do you want me to take a turn in the hold at WOBUB or turn straight in?" He responded, "Thanks for asking! Turn straight in at WOBUB." Fine. Now I have to figure out how to convince the 530 to skip the hold.

Well, necessity is the mother of invention. I got to the IAF, hit the FPL button, highlighted the FAF and hit Direct. The 530 didn't miss a beat, turning northeast onto final. I descended to 1500 and started watching for the airport. I crossed the FAF, which is a bit over 4 miles from the threshold -- still no joy. Started my descent to MDA (680 in this case) and about 3 miles out I saw the red lights of the PAPI...so I stopped descending and waited for some white lights. Runway lights showed up and the actual landing, in light rain, was uneventful.

This was maybe the fifth time since I got my instrument rating that I flew an approach because I had to. It's fun! The Garmin GNS-530 is a wonderful machine. Approach controllers are the nicest people. And it's nice to know that the ILS approach to the 7000 foot runway at Manassas is in your back pocket if you need it.

Here's the flight, by the way.

Friday, March 27, 2009

Annual Inspection (VI)

The parts are in and I've been assured that I'll have an airplane at 5 PM to fly to DC. I am fully aware that I am going off on a longish cross-country flight immediately after maintenance. In my defense I will point out that the weather is VMC and the sun won't be setting for quite some time -- so if I get any maintenance-induced failures, I'll have options.
I've filed for the usual routing...Sparta to East Texas to Lancaster to Baltimore to home...and the computer is predicting 2:18 en-route. If I can get out soon after 5:00 PM I should arrive at KVKX around 7:30.

Next week I'll bring the airplane back to Three Wing to clean up a couple of exterior items:
  • Address the bit of corrosion on the belly;
  • Paint one of the VHF antennae.

Thoughts on the ELT

The installation of an Emergency Location Transmitter (ELT) was mandated by Congress in 1973 in the aftermath of the disappearance of Rep. Hale Boggs' flight in Alaska. N631S still has installed the ELT that was delivered with the airplane in 1977.

Like most airplanes of a certain age, this ELT is designed to be activated by the deceleration forces associated with a crash and to broadcast a signal on the designated emergency frequency, 121.5 MHz. For some time, this signal could have been detected by an orbiting satellite that would provide location information to search-and-rescue (SAR) agencies who would then further localize the signal and effect a rescue. At least that was how it was supposed to work.

In fact, the 121.5 MHz ELT's are quite unreliable. They cannot be counted on to activate in the event of an accident. In fact they are so bad that they are being superceded by a new generation of ELT's that will operate at 406 MHz and will provide much improved performance. (These new units will also emit a signal at 121.5 MHz so that the SAR folks can deal with the last stages of the search without needing to procure all new direction-finding receivers.)

As part of this transition to the 406 MHz technology, the orbiting SAR satellite stopped "listening" for 121.5 MHz signals on February 1, 2009. Now, if you crash and your old 121.5 MHz unit activates (a very big if) you are dependent on passing aircraft monitoring that frequency to detect you.

So, what are the options?
  • Upgrade to a 406 MHz ELT and enjoy the benefits of the new technology. This will set you back about $2,000 (including cost of installation) for a basic unit or about $5,000 for one that is coupled to your GPS and will, when activated, broadcast the lat-lon of your crash site.
  • Keep the old 121.5 MHz unit in the airplane, for what it's worth, and invest about $500 in a 406 MHz Personal Locater Beacon (PLB) to carry with you on every flight. The drawback of the PLB is that you have to be conscious and capable of activating it manually -- it has no self-activation mechanism.
  • Just keep the old 121.5 MHz unit. It complies with US regulations (though not with Canadian nor Mexican regs) but you probably should not count on it to get you rescued with any speed.
If money were no object, I'd be having a 406 MHz unit installed in N631S right now. Even with money being a rather significant object, if my missions involved extensive flights over mountainous or desolate terrain, I'd be upgrading to a 406 MHz system.

But with virtually all of my flying being done in the "civilized" environs of the Northeast and under IFR (therefore in virtually constant contact with Air Traffic Control), I feel comfortable keeping the old unit in place, and maybe acquiring a PLB. Thus, during the current annual inspection we are replacing the ELT's battery as the regs require. It's just a brick, but it's a legally necessary brick.

I'll discuss PLB's in a later post.

Annual Inspection (V)

Now we are waiting for the arrival of two parts. The flexible boot for the inlet duct was supposed to arrive yesterday -- but didn't. And when the mag that was due for its 500 hour inspection was opened up, the impulse coupling was found badly pitted so we have one of those in transit. If the brown truck brings the needed parts mid-morning then there is a good chance I am flying south today. If not, I am on the train.

Other than that, there have been no additional unpleasant surprises. This is coming together as a pretty low-stress annual. Further, anon...

Thursday, March 26, 2009

Annual Inspection (IV)

As of this morning Mike the IA has finished everything except the nose gear. Not much in the way of bad news today:
  • The ELT battery is due for replacement. I need to make a separate post on my thinking about the ELT.
  • There is some corrosion starting on the belly behind the battery drain; needs to be cleaned up, alodyned and touch-up painted -- but maybe not this week.
  • The pilot's side seat rails have worn to the point where the applicable AD requires that they be inspected at 100 hour intervals rather than annually. No further action at this time.
The expander boot for the carb inlet air duct is due in today; we are still working on the assumption that the airplane will be done and available Friday (tomorrow!) afternoon.

Wednesday, March 25, 2009

Annual Inspection (III)

As noted earlier, it's time to replace the bellows-thingy in the carb inlet air duct. Normally I would dig out my parts catalog and look for the part number, then search on CessnaParts.com or on "I Want Cessna Parts" (aka Premier Aviation) to check price and availability. But I'm here in Connecticut and the parts catalog is back home in Virginia.

Once again, it is Cessna Pilots Association (CPA) to the rescue! CPA is a "type club" (and an excellent one, at that). It maintains an extensive web site with a very active members forum. I posted a query in the "Maintenance" section and in a couple of hours I had a response from a member in California that provided the part numbers I needed.

Y'all pay 'tenshun here: If you fly a Cessna you cannot make a better expenditure than the few bucks ($55, I think) for annual membership in CPA. Every year without fail, I learn things that save me far more than the membership fee. CPA is a Very Good Thing!

Anyway, now I know that I need p/n 0752016-7, officially an Expander Boot. Either of the previously referenced sources will sell me one for about $75. By the way, it is most fortunate that I only need the silicone rubber boot and not the entire assembly including the associated aluminum bits. The assembly would cost $1,318.50. (Ouch!)

Let me put in a few words of praise for the Cessna Aircraft Co. on the subject of parts. OK, they aren't cheap. But as a matter of policy, Cessna sees to it that I can get the parts I need to maintain my 32 year old airplane. Not every owner of an older airframe has that comfort level.

I shared the results of my research with Three Wing and they assure me that they are on track to get the boot in-house in time to support completion of the annual by Friday.

So far, so good...

Annual Inspection (II)

The annual proceeds apace. I stopped at the hangar this morning and reviewed "squawks thusfar" with Mike the IA. Mostly trivial. Three items deserving of note:
  • The flexible bellows in the carb inlet air duct in the lower cowl has chafed through rather badly. Not judged repairable. So they are starting to research getting a new one, which may generate a separate post on the cost of Cessna parts. Also, the actual replacement of the bellows is a fussy little job -- a bunch of rivets.
  • One of the Slick magnetos is due for its 500 hour inspection.
  • There's a crack in the baffling at the forward end of cylinder #6. Looks like an aluminum L-shaped doubler and a couple of rivets are in order.
Mike expects to finish up the inspection later today (or tomorrow morning at the latest). It is looking reasonably likely that I can have N631S back by Friday for my weekly trek to DC.

Tuesday, March 24, 2009

"One-One Thousand, That's Eleven Thousand"

On my northbound commute from DC to Bridgeport, I get routed over Kennedy Airport (KJFK) and so get to listen to the estimable New York Approach controllers doing their thing. In assigning altitudes to their departures and arrivals, they state the numbers twice, in different ways, like: "American 79 Heavy, climb and maintain one-one-thousand, that's eleven-thousand." (The flight crews will usually read back the instruction using the same phraseology.)

A question showed up on another blog concerning the rationale behind this phraseology, which got me to googling -- and led me to the ASRS analysis that I've linked to the title of this post. It turns out that the "(varied) numbers twice" procedure is a tool to minimize miscommunicated and misunderstood altitude assignments. Click on the title and read the analysis -- good stuff there.

By the way, Order 7110.65 (the Controller's Bible) permits but does not require use of this phraseology.

Annual Inspection (I)

The flight yesterday morning from VKX to BDR was a longish 2.3 hours. On arrival I taxied to the Three Wing maintenance hangar and handed the airplane over to the wrench turners.

I stopped off at the airport this morning to check on progress. N631S is in the hangar, with all of the inspection covers opened, the cowling removed and the interior stripped. Mike the IA said he really had only just started inspecting, but that the cylinder compressions were all acceptable. Other than the need to replace a couple of stripped screws, he's found nothing so far to cause concern.

I've told the folks at Three Wing that this year's watchword is Frugal. Given the current economic conditions, we are going to defer anything that is deferable, consistent with making no compromises on airworthiness. They say that they "get it", and that every owner/operator is telling them the same thing.

I shall visit them again tomorrow, by which time Mike should be nearly done with the inspection.

Sunday, March 22, 2009

Another Round Trip

N631S and I left KBDR at 1730 local time on Friday afternoon and had (unusually) a tailwind for the trip down to VKX. The 2.2 hours logged pushed me over 800 hours as P.I.C. It looks like there will still be a northerly flow tomorrow morning for the trip back to Connecticut, so I can expect a bit of a headwind. Then the airplane goes to the shop for this year's annual, about which more anon.

Wednesday, March 18, 2009

Reference Map for AIRMET/SIGMET Vertices

It occurs to me that I may not be alone in needing a tool to help visualize the geography of a textual AIRMET or SIGMET. Click on the title of this post to get to a very nice reference map from the Aviation Weather Center folks, in .gif format. I keep a printed copy in my flight bag.

Plans Change

The shop at Three Wing has gotten backed up with emergent work. (Mainly, they seem to have had an annual on a Navaho blow up on them, in the process dynamiting their schedule.) In any event they have not yet started on N631S's annual. So, I have suggested pushing it off to next week -- and that's been accepted with alacrity and appreciation. I get to fly home on Friday evening and back here on Monday morning. Cool!

The only rub is that right now I have about 48 hours on the oil. A round trip home will add about 4.5 hours more. Skip (Three Wing's maintenance jefe d'oro) says that's no problem but I am not accustomed to running oil that long -- However, I've been flying regularly and the engine seems very happy, so I will accept it.

Tuesday, March 17, 2009

Daily FAR

I've just added a "Gadget" at the bottom of the page that (if I understand it correctly) displays a randomly selected section from the CFR Parts applicable to aviation. I have set it to use Part 61 and Part 91 for source material -- it also has Parts 121 & 135 available but those are not of current interest to me.

You can have a look by pressing your "END" key. I'll keep it there for a while and see how it works out.

Since Grandma was an O'Rourke...

...I would be remiss in not saying,



On the Monday following the flight discussed earlier there was considerable risk of icing between the DC area and Connecticut, so Amtrak had the benefit of my patronage...which naturally put me on the southbound train last Friday, the 13th. Lucky me. Monday (yesterday) was a different story.

Departure from KVKX at 08:00 AM local time was strictly an IMC affair. Ragged ceiling around 800 feet and 1-3/4 miles visibility according to the on-field AWOS

I picked up my clearance by telephone from Potomac Departure Control, got 631S started and run up, then called back for IFR release. On every previous occasion when I've done that, I have gotten an immediate release with a void time a few minutes in the future. This time I got, "You are released at 1205; clearance void if not off by 1211; the time now is 1158-and-a-half." First time I've ever had a release that began some minutes into the future. No problem, just different.

I departed and was quickly into the schmoo. The freezing level was reported up around 10,000 MSL in the DC area, sloping down to 5,000 up around Bradley (KBDL), so I knew I'd have no icing problem all the way to KBDR. Potomac Approach got me radar-identified and turned me to 090 degrees but kept me at 3,000 MSL quite a while longer than usual. Just before turning me over to Dover Approach they cleared me up to 5,000 and I got into bright, beautiful VMC conditions at about 3,500. The rest of the flight was VFR and routine.

On arrival at Bridgeport I parked at the Three Wing Flying Services maintenance hangar and turned N631S over to Skip and Tony for the 2009 Annual Inspection. The next few posts here will probably be about that.

Saturday, March 7, 2009

Friday, BDR to VKX

In the event, the flight was uneventful -- but very long! The original GFS model verified; by 1600 local time on Friday Bridgeport offered clear skies. The west-bound portion of the flight was beset by headwinds out of the southwest on the order of 40 knots. I logged 3.1 hours for the flight to VKX.

Now the process begins all over again, as I must assess the chances for a flight back to KBDR on Monday afternoon.  

Thursday, March 5, 2009

Flight Planning for Friday (IV)

As the flight gets closer, available weather guidance gets more specific. We can now begin to look at applicable TAF's. The Terminal Area Forecasts for major hub airports look 30 hours into the future. Here (obtained from the National Weather Service's Aviation Weather site) are the TAF's from this afternoon for Kennedy, Baltimore-Washington Int'l, and Dulles:

KJFK 052021Z 0520/0624 18010KT P6SM BKN250
FM060900 20012KT P6SM OVC120
FM061500 21015KT P6SM SCT020 OVC050

KBWI 051720Z 0518/0624 15006KT P6SM FEW250
FM060100 15004KT P6SM BKN150
FM061400 22010G18KT P6SM SCT030 BKN050

KIAD 051720Z 0518/0624 19005KT P6SM FEW250
FM060300 17005KT P6SM BKN150
FM061400 20010G18KT P6SM SCT030 BKN050

For departure, the KJFK TAF tells me to expect winds from 210 at 15 knots, good visibility, no significant weather, and scattered clouds at 2,000 feet with an overcast above at 5,000. That forecast is valid from 9 AM until the end of the TAF period, 7 PM or 00Z.

The TAF's for KBWI and KIAD indicate that for arrival the wind should be from about 210 degrees at 10 knots with gusts to 18. Again, good visibility and no significant weather. The clouds are forecast to be scattered at 3,000 feet with the same 5,000 foot overcast.

Rechecking the freezing level chart tells me that the freezing level is still forecast to be at least 8,000 feet above ground so even if I need to fly through clouds above the overcast I should have no concerns about ice. And when I arrive in the DC area conditions should be good for a visual approach and landing.

Tomorrow, I'll make a final assessment of the weather and file my IFR flight plan.

Wednesday, March 4, 2009

Flight Planning for Friday (III)

The nice folks at Wunderground provide a number of elegant aviation-related weather maps (as usual, see the link list at right). Here's a small segment of the freezing level map forecast for 00Z on Friday.

The medium blue color indicates a freezing level about 8,000 feet AGL (Above Ground Level). The gold color indicates freezing about 11,000 feet AGL. So, if the forecast is valid any clouds I encounter at 8,000 feet or below should be free of icing.

A quick cross-check of both the GFS and NAM temperature predictions at the 5,000 foot height gives similar results.

When I file my flight plan the Air Traffic Control folks will assign a route based on their need to keep me away from commercial traffic in and out of the New York area. I can request whatever I want...what I will get is a route taking me west from Bridgeport to Sparta, NJ at 8,000 feet, then south to Solberg in central NJ then west again to Allentown, PA then south over Reading and Lancaster, then southeast to Baltimore, south past Andrews AFB and a last short westbound leg into Potomac Airfield.

If you picture that routing overlaid on the freezing level map you can see that I should be in good shape, even if the NAM forecast turns out to be right.

So as of now (midday Wednesday) I'm optimistic about making the flight on Friday evening. Tomorrow after lunch, we can look at the TAF's (Terminal Area Forecast) for the major airports (i.e., Kennedy, Baltimore and Dulles) because they look out 30 hours. That will be our first chance to work with specific forecasts. And, we can settle on a flight plan!

Flight Planning for Friday (II)

Here is the latest MOS output for KBDR from the GFS Model. (That stands for Global Forecast System.) It's based on the 12Z model run on Wednesday, March 4th, and looks 84 hours into the future. The block of time we are interestd in is from 21Z Friday the 6th to 00Z Saturday the 7th.

KBDR   GFS MOS GUIDANCE    3/04/2009  1200 UTC                      
 DT /MAR4   /MAR5                   /MAR6                   /MAR7
 HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06
 N/X                    14          40          31          45   
 TMP  28 29 26 24 20 18 17 29 37 39 36 34 33 33 34 37 42 43 42 40
 DPT   8  9 11 11 10  9  9 13 17 21 25 26 29 30 31 33 36 38 38 35
 WDR  29 29 28 30 29 31 31 26 22 20 19 20 21 20 22 25 26 25 26 27
 WSP  10 09 06 04 04 04 02 04 06 06 06 08 07 07 10 12 13 09 07 04
 P06         0     0     0     0     1     6    24    18     3  0
 P12                     0           1          27          22   
 Q06         0     0     0     0     0     0     0     0     0  0
 Q12                     0           0           0           0   
 T06      0/ 0  0/ 2  0/ 0  0/ 0  0/ 0  0/ 0  0/ 0  0/ 0  1/ 3  0
 T12            0/ 2        0/ 0        0/ 0        2/ 0     1/ 6
 POZ   2  2  0  1  0  0  2  1  2  1  4  6 18 18 13  5  4  2  0  0
 POS  87 95 95 95 94 91 96 97 93 88 71 29 19 11  1  0  0  0  1  4
 TYP   S  S  S  S  S  S  S  S  S  S  S  R  R  R  R  R  R  R  R  R
 SNW                     0                       0               
 CIG   8  8  8  8  8  8  8  8  8  8  8  8  7  7  8  6  7  8  8  8
 VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  2
 OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N FG

As you can see, this model is forecasting a temperature of 43 deg F at 21Z on the 6th (that's 4 o'clock in the afternoon EST) with a 5 degree spread between temperature and dew point. The probability of precipitation is very low (3% or so) and the ceiling and visibility are both expected to be good. (An "8" for ceiling means that any solid cloud deck will be at least 12,000 feet up and a visibility of "7" means you can see more than 6 miles.) Note that the model is calling for fog to develop around 06Z (about 1:00AM), reducing visibility to less than a mile.

If you use the link at right (in my link list) to look at the MOS site, you can check on the forecast for this block of time at other stations on the expected route. I've had a look at Lancaster, PA (KLNS) and Washington, DC (KDCA) and found similar conditions -- temps in the low 50's at Lancaster, high 50's at DCA...low POP's, high ceilings and good viz in both places. The model forecasts winds at DCA from 210 deg at 7 knots at 00Z. This is all good!

While we're at that site, though, we should look at the forecast from a different model, the NAM (North American Mesoscale model). This model crunches the data differently and is not nearly so encouraging! For Bridgeport it predicts a temperature of 41 degrees F, a POP of about 30% and an overcast between 1,000 and 1,900 feet above the ground (albeit with good visibility underneath). Lancaster has 48 degrees and a 25% POP with the overcast between 3,100 and 6,500 while at DCA the model forecasts 54 degrees, minimal POP and the ceiling up to between 6,600 and 12,000 feet with wind from 220 degrees at 7 knots.

So if the GFS model is right then visual flight conditions will prevail...but if the NAM model has it closer then it's IMC for at least the beginning of the trip. This makes it very important to understand how far above the ground the freezing level will be. We'll look at that in the next post.

Tuesday, March 3, 2009

Flight Planning for Friday (I)

Here  it is Tuesday afternoon. Since the plan is to depart KBDR at about 1700 local on Friday the 6th for a flight down to KVKX in Maryland it becomes a good idea to look at the expected weather. I generally begin with the forecast map put out by NCEP (National Centers for Environmental Prediction), a part of NOAA. (See my link list at right.)

This is the Day 3 Final forecast map, issued at 1754Z on Tuesday and valid at 12Z on Friday. The low over Ontario will be trending to the northeast, dragging the associated fronts along for the ride. So by departure time, about 22Z, the entire route of flight from Connecticut to the DC area ought to be in the warm sector between the warm front and the cold front.

Initial thoughts: I am concerned about rain; I wonder if the warm air will interact with the snow pack to induce fog; I wonder whether the temperatures aloft in the warm sector will allow flight in IMC (Instrument Meteorological Conditions), which is to say in the clouds, without icing concerns.

Tomorrow, we'll take a look at the MOS (Model Output Statistics) which have an 84 hour time horizon. That will give us POP's (Probability of Precipitation) from a couple of models for the period of interest...and we'll look at forecast upper air graphics to get an idea of what to expect for freezing levels.