Thursday, March 29, 2012

2012 Annual Inspection (vii)

The last part that N631S needed – the seat roller-assembly bracket (previously discussed) – showed up yesterday. It was installed and the airplane has been closed up. Basically, we're done. All that remains is for Mike the IA to do a run-up, me to do a brief test flight, and Mike the Maintenance Manager to work up the invoice.

The old seat roller bracket, pictured at left, is my new high-priced paper weight. I estimate that it weighs about 80 grams, so that's about $5.37/gram (or, if you prefer, $153.40/ounce). As usual, if it says "airplane" on it, it's pricey. And at least Cessna parts are generally available no matter how old your airplane may be. There are lots of folks flying other manufacturers' aircraft for whom parts are unavailable at any price. They wind up needing to fabricate parts from scratch to keep their airplanes flying. Therefore, I shouldn't complain!

While I was at the hangar this morning the guys opened the door and pushed N631S out under a cloudy Connecticut sky, making room for the next airplane. Assuming no squawks today from the run-up or the test flight, we're done for another year. Tomorrow afternoon N631S and I will be off to the DC area in the usual way.


Tuesday, March 27, 2012

2012 Annual Inspection (vi)

The "inspection" part of N631S's annual maintenance ritual has been completed. Mike the IA had the nose landing gear apart and inspected on Friday. That was the last major sub-system and it didn't provoke any squawks. Now, it only remains to complete the emergent work items and close the airplane up again.

Yesterday, the new muffler (first discussed in this post) showed up. Mike had soaked the exhaust manifold flange nuts on both sides of the engine with penetrating oil over the weekend and he set about breaking those joints so that the old muffler could be freed. Naturally, exhaust system fasteners being the way that they are, it was a bit of a struggle. But when I showed up this morning, the old muffler was out and the new one was ready for installation (see photo above).

With the old muffler out it was easy to get a good look at its innards. In the picture at left you can see how badly the flame cone is warped and cracked. This component was refurbished seven years ago and has since had over 900 hours time-in-service. In that time, on the order of 400 tons of corrosive exhaust gas have passed through it, at temperatures in the neighborhood of 1,400°F. As I said a few posts ago, it's a hard life and there's no question in my mind that it was time for a new one.

Today, a new seat roller assembly and a new magneto distributor block should have arrived. Those will get installed tomorrow as the bits and pieces start going back together. The plan is to run up the engine and test fly the airplane on Thursday afternoon, and then for N631S and I to make the trek back to the DC area on Friday.


Friday, March 23, 2012

2012 Annual Inspection (v)

There are no new items to talk about today in connection with N631S's annual inspection, but some aspects of compliance with the Seat Rail Airworthiness Directive (AD) warrant further discussion.

As mentioned in yesterday's post, Mike the IA measured the rails and the roller assemblies as required by AD 2011-10-09, and all was in order except for one roller assembly that will be replaced. But the AD, in addition to specifying the actions required for compliance, adds:

"Repetitively thereafter do the actions at intervals not to exceed every 100 hours TIS or every 12 months, whichever occurs first..."
This differs from the old AD which basically required recurrent action annually. Since N631S and I have been flying about 150 hours each year this would mean an extra time for the seats to come out and the inspections to be accomplished. That's a non-trivial amount of work (and cost)!

Fortunately, the FAA recognized that a 100 hour recurrence interval is burdensome for owners of "personal" aircraft to a degree that isn't commensurate with the resulting reduction in the risks that the AD was intended to ameliorate. So, the Small Aircraft Directorate at the Wichita Aircraft Certification Office provided relief in the letter reproduced at left (click to enlarge), authorizing an Alternate Method of Compliance (AMOC) with the AD.

The AMOC letter states:

"Aircraft owners/operators who do not operate for the purpose of carrying any person for hire or to give flight instruction are no longer required to perform the seat track inspection in AD 2011-10-09, paragraph (g) at 100 hour intervals, and may instead perform these inspections at 220 hour intervals or during annual inspections whichever occurs first."
So...hooray! N631S is back to annual inspection of the seat rails and rollers, at a time when the seats are out of the airplane anyway. But (there's always a 'But'), there is one more complication. The AMOC letter also says:
"Before using the AMOC, you must notify your Principal Inspector in the Flight Standard District Office (FSDO)."
In most cases, that's pretty straightforward. But the address on record for N631S is in Virginia while compliance with the AD is being accomplished in Connecticut. Which FSDO should we call – Dulles or Bradley? So, I called the FSDO at Dulles, got the duty Airworthiness Inspector on the line and asked him. He thought about it and said that we should notify the FSDO at Bradley, because the notification is connected to the accomplishment of the AD and that work was being done within the Bradley FSDO's territory.

On Monday I'll report all of this to Mike the IA so he can log it all correctly, and then we're good on the seat rail AD for another year.


Thursday, March 22, 2012

2012 Annual Inspection (iv)

When I spoke with Mike the IA this morning about progress on N631S's annual, he pointed out that both magnetos were due for their 500 hour inspections. This did not require a difficult decision...the work needs to be done. He'll be taking both mags apart, inspecting their innards, and replacing any worn parts.

The Slick magnetos that generate spark for the airplane's ignition system are very simple devices, but subject to wear and tear. Failing to maintain them properly can ruin one's day. This point is made well in this post from the blog of the late and sorely missed Neptunus Lex.

And, by the way, Lex links to a delightful site that explains the design and operation of magnetos in an innovative way. Most highly recommended!

As I was leaving the hangar, Mike was about to start inspecting the seats and seat rails in compliance with an applicable Airworthiness Directive (AD 2011-10-09). This AD is a recent revision to one of long standing that required inspection of the seat rails for wear (Cessna seats having exhibited an unpleasant tendency to come adrift at awkward times in cases of excessive wear). The 2011 version added new guidance covering wear of the roller assemblies that ride on the rails as the seat is adjusted.

A couple of hours later I got an e-mail telling me that there was good news and bad news. The good news was that the rails are fine – within the wear limits specified by the AD. The bad news is that one of the roller assembly housings (see photo) is worn out of limits and will have to be replaced.

The full width of the housing is 0.900" and the maximum gap permitted between the tangs, as annotated on the picture, is 0.440". This one is worn to a gap of about 0.465". It has to go. And Cessna is, it seems, very proud of their parts. A new roller assembly, P/N 1714000-33, will be setting me back $426.66. Fortunately, it's a simple bolt-on installation so there won't be much additional cost for labor. And I can count myself as fortunate that only one roller assembly needs to be replaced. This time.

The only other bit of significant news is that a new muffler (discussed previously) has been ordered and is expected to arrive Tuesday next. That keeps everything on schedule.


Wednesday, March 21, 2012

2012 Annual Inspection (iii)

There were several things to think about after this morning's visit with Mike the IA and 31 Sierra. A good chunk of the "firewall forward" part of the inspection is done and the only significant issue concerns the muffler. It's a hard life for the muffler, with a constant flow of 1,000+ degree exhaust gas passing through it, so it isn't a surprise when problems develop.

Mike feels (and I agree) that the flame arrestor (the perforated tube visible through the exhaust pipe, at left) is deteriorated beyond acceptability. There are a couple of options available to address this – repair or replace. The decision will be affected by both price and schedule.

Dawley Aviation in Wisconsin is known to do a good job refurbishing these mufflers. They charge $225 if they can reuse the shell and $298 if they can't. The problem is that with a two to three day turn-around, sending the muffler there would require either use of extremely costly overnight shipping or accepting the idea of N631S being grounded through an extra weekend.

You can buy a brand new muffler from Cessna – but they want about $2,000 for it (I kid you not). However, a high-quality aftermarket replacement is made by Wall-Colmonoy. Their Nicrocraft line of exhaust parts is carried by Aircraft Spruce and this unit (part number 0750161-89) can be had for $332.95 plus shipping. This may cost a few dollars more than the repair but the timing will be better.

I had asked Mike to have a look at the connectors for the flow transducer (seen at left) that feeds its signal to the Shadin fuel flow computer. For about the last year, the unit has periodically suffered from erratic behavior. But it would recover after a few hours and when it is working it works perfectly. I've acquired a replacement transducer, but I'm reluctant to remove the old one while it's working. There appear to be no problems associated with the wiring, so we'll cover it back up and wait for it to fail. Fortunately, it's not essential for flight and it's readily accessible with the lower cowling removed so it makes sense to wait.

Finally (for today), we are replacing the plastic end caps on the right horizontal stabilizer and the right side of the elevator. A few "smoking rivets" have shown up there and Cessna has a service bulletin (number SEB03-1) covering the area. It calls for increasing both the number and size of the rivets. But the plastic end caps are cracked and likely not salvageable, so they'll be replaced. The image at left is from the service bulletin, showing the area in question.

I'll be stopping off at the airport tomorrow morning, of course, to see what new things are in store.


Tuesday, March 20, 2012

2012 Annual Inspection (ii)

This morning I stopped by the hangar to visit N631S, collect the various loose items for storage, and see how the inspection was progressing.
Before anything was taken apart, Mike the IA did a pre-maintenance run-up and found no discrepancies. The airplane is decowled, the old oil drained, and the main gear fairings are off. The upper spark plugs have been pulled; they look good. Work continues on opening the inspection covers and removing the interior.

The results of the engine's cylinder leakdown check (i.e., the "compression test") look quite nice. Mike checked the cylinders for leakage as instructed by TCM Service Bulletin SB03-3. Last year, one cylinder, #2, was not very tight. It tested at 48/80 psi on a day when the minimum acceptable value based on the standard orifice was 46/80. This year, on a day where the minimum acceptable value was 48 psi, it performed better. From the logs, here are the compression values at each annual inspection since 2007 (charted below):

Obviously, cylinders #2 and #4 were having a much better day this year than in 2011. N631S's engine is now at 1567.4 hours since its last major overhaul and oil consumption never exceeds 2 quarts during each 50 hour oil change interval. I anticipate that no surprises will arise from spectrographic analysis of the used oil, or from the visual inspection of the filter media or from the borescope inspection of the cylinder interiors. It looks to be a healthy engine and there appears to be every chance that it will happily run well beyond the nominal 2000 hour TBO period...at least I hope so!

As usual, I'll be stopping at the hangar tomorrow morning to see what items of interest Mike has found today.


Monday, March 19, 2012

2012 Annual Inspection (i)

Once again it's time for N631S's Annual Inspection. Last year the Annual was 'signed off' early in April so this year's inspection could have started as late as April 30. But I am otherwise engaged next weekend and the oil is nearly due for changing so this seemed like a good time to turn the airplane over to Three Wing Flying Services for about two weeks.

Actually, I've asked that they target Thursday,March 29th as the completion date. That will let me get a test flight in and have the next day, Friday, available for resolving any lingering 'squawks' prior to an IFR flight back to the DC area.

There's an administrative change in how the work package is being managed this year and I think it's a good one. As I've noted before (for example, here), the Annual Inspection is neither more nor less than is specified in Appendix D to Title 14 CFR 43. Usually, however, there are a number of maintenance actions that get accomplished in conjunction with the inspection but that are charged for separately. Three Wing has chosen to offer a "Flat Rate Package" encompassing the Annual Inspection and the associated Maintenance items for one fixed price. I looked at the proposal and compared it with the actual costs of N631S's last three Annuals, and concluded that the Package was reasonable and fair.

So, we've agreed that items beyond the inspection, estimated to require 13.9 man-hours, will be part of the Flat-rate Package. These include the engine compression check, the oil change, and servicing of spark plugs, magnetos, flight controls, landing gear and wheel bearings. Assorted filters and screens will be cleaned and serviced, the prop will be dressed and painted and the ELT will be inspected. Add the estimated 17 hours for the actual Annual Inspection, and the package totals 30.9 labor hours. At a shop rate of $86/hour that means I've spent $2,657.40 before any emergent work items revealed by the inspection are addressed. (I think I already know about a couple of those, to be discussed in coming posts.)

If all went according to plan, today Mike the IA did the maintenance run-up, checked the cylinder compressions, and started to open up the airframe. More on all that tomorrow.


Sunday, March 18, 2012

Something Happened

Something happened on this day thirty-five years ago in Wichita, Kansas. A Cessna Aircraft Company production test pilot named Jim Ballard picked up a blank Aircraft Log. On the cover next to the 'N' he entered '631S' and next to 'SERIAL NO.' he wrote '18265554'. Then he turned the page and on the first leaf, next to 'Record of' he entered 'Cessna 182Q 18265554 N631S'. On the next line, next to 'With Engine' he wrote 'Continental O-470-U 465712'. Then he went out on the ramp at Wichita's Mid-Continent Airport to meet the machine whose birth as an airplane he was about to facilitate.

Jim certainly performed a careful pre-flight inspection, then he climbed into the cabin and started the big Continental six and, with concurrence from the tower, taxied for departure. Senses alert for any sign of defect or maladjustment, he took the machine off the ground and into its natural element. For 1.3 hours he checked and verified, in accordance with his production test check-list, the readiness of this machine to be sent on to its new owner-pilot. Then he landed, back where he'd begun.

After shutting down he opened the Aircraft Log once again and turned to the first page for the recording of flight data. He filled in the year, '77', and the day, 'Mar. 18'. Under From, 'Ict' and under To, 'Local'. Nature of Flight is 'Test', and Duration of Flight is '1.3'. And then he signed the column labeled Signature of Pilot...'Jim Ballard'. N631S had passed its test.

Thirty-five years later...two engine overhauls later...nine owners and 4,235.2 tach hours later...N631S continues to pass each test, to be a machine admirable in every respect. As the current caretaker, my gratitude flows to Jim Ballard and to every owner and pilot who has cared for and worked with this airplane in the intervening years. I'll try to be worthy of the airplane you've entrusted to me.

Saturday, March 17, 2012

Now for Some Real IFR! (cont'd)

This will be an update on the flight that was anticipated in yesterday's post. Yes, I did manage to get N631S wet...and no, not so very wet after all.

This was the METAR on offer for our departure from KBDR:

KBDR 161952Z 09005KT 10SM OVC005 07/04 A3013 ...
Wind out of the east at five knots, good visibility and a low overcast. We took off from Runway 6 and entered the base of the cloud layer at 500 feet, as advertised, then emerged from the tops at 2,400 feet into bright sunshine. And that was the last cloud we saw for quite some time.

Looking ahead an hour and a half later, from somewhere near Lancaster, the on-board NEXRAD display showed showers in the vicinity of our destination, KVKX. I watched them for a while and they just weren't moving. Low level winds were very light and there was nothing to motivate those showers to 'move along.' But there didn't appear to be any reason for concern. The METARs from Washington National (KDCA) and Andrews AFB (KADW) showed light winds and good visibility. I thought I might even get away with a visual approach at KVKX:
KDCA 162252Z 00000KT 5SM BR BKN100 BKN200 14/12 A3015 RMK AO2 RAE10 SLP209 P0000 T01440122

KADW 161955Z AUTO 08003KT 9SM -RA OVC028 14/11 A3015 RMK AO2 RAB1918DZE1918 CLDS LWR SLP212 P0000 T01410113 $
The patch of showers never did depart the area and the view out the right-side window as I flew south from Baltimore to the Nottingham VOR (OTT) did not give me a warm feeling about the visual approach. So I asked Potomac Approach for vectors for the RNAV Rwy 6 instrument approach which they cheerfully provided. N631S and I flew through some light rain on final but when we landed the runway was dry.

Would I have been able to complete a visual approach without any problem? In all likelihood, yes. Was asking for the RNAV approach the conservative thing to do? You bet!

Friday, March 16, 2012

Now for Some Real IFR!

The cold temperatures prevailing aloft for the last few months have ensured that most flights conducted under Instrument Flight Rules (IFR) have actually proceeded in Visual Meteorological Conditions (VMC)...i.e., there's been ice in them clouds! So today I'm looking forward to actually getting N631S wet! I'm planning a departure a bit after 20Z from Connecticut and expecting a route over eastern Pennsylvania then down over Baltimore and into the DC area.
The key to this is a really big bubble of warm air over the middle of the country, working its way east. The plot at left shows the freezing isotherm for around 9,000 feet MSL projected to be well to the north of my flight path. (You can click on the image to make it bigger.) So whether there are clouds in my way, or not, doesn't matter much. I can be fairly certain that icing won't be an issue today.

Of course, you do have to take off and land. For those purposes, the forecasts for my departure and arrival airports are fairly benign. Here are the current Terminal Area Forecasts (TAF's):

KBDR 161325Z 1613/1712 12009KT P6SM OVC015 
     TEMPO 1613/1615 4SM -DZ BR BKN006 OVC010 
     FM161600 VRB05KT P6SM BKN010 OVC030 
     FM162300 VRB04KT P6SM SCT025 BKN040 
     FM170400 VRB03KT 4SM BR SCT020 OVC040 
     FM170700 VRB03KT 2SM BR BKN020
KDCA 161122Z 1612/1712 04007KT 4SM BR OVC006 
     FM161400 VRB04KT P6SM BKN008 OVC100 
     FM161500 VRB04KT P6SM BKN060 OVC100 
     FM161700 20005KT P6SM VCSH BKN050CB OVC090 
     FM162100 VRB03KT P6SM -SHRA BKN040CB OVC100
     FM162300 VRB03KT P6SM FEW040 OVC100 
     FM170300 33004KT P6SM BKN100
The pertinent forecast lines are highlighted in red. For departure from KBDR it looks like I should expect light winds, good visibility, and a broken ceiling at around 1,000 feet, overcast above. Arriving in the DC area I can look for light rain showers beneath a broken 4,000 foot ceiling of cumulonimbus (CB). The presence of CB's in the TAF implies a chance of convective activity, but not enough for thundershowers to be part of the forecast. And, as it will be getting on toward the valid time for the next line in the forecast (from 23Z) as I get there, conditions may be improving.

It looks like it should be a good flight.

Friday, March 9, 2012

Are you Sinistral? (cont'd)

Two weeks ago I posted a request for pilots visiting this blog to participate in a survey, asking whether they were "left handed." I recognize (now, as I did then) that this is thoroughly unscientific. There is much more to handedness (or laterality or chirality) than which hand you use to pick up a pen. Just speaking for myself, I would be classified in a more sophisticated study as mixed-handed or cross dominant. But the question under consideration is: does the pilot community as a whole reflect the "handedness" of the general populace? Perhaps the survey result would be an indicator.

I leave it to you to decide whether the result is significant. Here's what emerged:

  • Total respondents: 91
  • Respondents self-identified as "left handed": 30
  • %'age of "left handed" respondents: 32%
  • %'age of the general populace "left handed": about 10%
  • Factor by which left handed pilots exceed general incidence of left handedness: about 3.2X
Actually, I'm surprised, having expected that the pilot community would be "handed" about like the general populace. Well, maybe not so much!

As vulnerable as this query is to confounding factors, it's hard to imagine a scenario that would explain away the entirety of excess left handedness among pilots reflected in the data. I have to conclude that pilots are, to a significant degree, more often left handed than "normal people."

Thursday, March 8, 2012

A Dark Cold Day

At about 0915 PST last Tuesday, Capt. Carroll 'Lex' LeFon, USN (Ret'd), died when the IAI F-21A Kfir that he was piloting crashed just inside the west gate of Fallon NAS in Nevada. I infer that he was returning from a sortie flown on behalf of his employer to provide "dissimilar type" aggressor aircraft services to the Navy so our young fighter pilots will be better equipped to stay alive and prevail in future encounters. As far as I'm concerned, Capt. LeFon died in the line of duty, serving our country.

There was another side to Lex. He maintained a blog at Neptunus Lex where he wrote eloquently of military affairs and the sea and politics and life. And flying. He wrote with an immediacy that pulled the reader into the cockpit and into the reality of flying the fast-movers. His writing could get your heart beating faster, could get your blood flowing. So I ignored (with difficulty) his politics and reveled in his exquisite tales of the airman's world. (The blog will be there; go on over and read his work.)

Lex retired from the Navy in 2008 and thought to make a second career working at a desk. But that ability was not given to him, so he went back to flying jets. Specifically the Kfir, which is sort of a tinfoil airframe wrapped around a roaring J-79 afterburning turbojet. He had to have loved it.

He also loved the poetry of William Butler Yeats. And so these words, taken from W.H. Auden's "In Memory of W. B. Yeats", seem to serve:

He disappeared in the dead of winter:
The brooks were frozen, the airports almost deserted,
And snow disfigured the public statues;
The mercury sank in the mouth of the dying day.
What instruments we have agree
The day of his death was a dark cold day.
- - - - -
But in the importance and noise of to-morrow
When the brokers are roaring like beasts on the floor of the Bourse,
And the poor have the sufferings to which they are fairly accustomed,
And each in the cell of himself is almost convinced of his freedom,
A few thousand will think of this day
As one thinks of a day when one did something slightly unusual.

What instruments we have agree
The day of his death was a dark cold day.

Carroll "Lex" LeFon, Capt., USN (Ret'd)
Gone West, 6 March 2012