After a weekend off, your new boss tells you that you are going to be starting airborne training starting on Monday and your excited and a little nervous. You have all of the SOPs in your head and have been practicing lots of hangar flying with your training partner. In my case, I had to travel from Fort Vermilion to High Level, Alberta, approximately a half hour drive North. Upon arrival at the High Level office, I could see the large hangar facility was the primary operations hub for the company’s maintenance and charter activities. Known for Northern lakes, fishing and amazing game hunting nearby, the charter operations were a going concern in the summertime. Charter Ops consisted of a Cessna Caravan and a number of Cessna 206 aircraft. The Caravan fleet was extremely busy in the summer hauling fuel barrels and other equipment into Forestry (fire bases) throughout Northern Alberta. In the winter this facility was primarily focused on the major overhaul of company aircraft.
The aircraft I was going to fly was in the main hangar, the hangar was busy with activity, aircraft being repaired, aircraft being prepped for charters, etc. My airplane, a 1994 King Air 200 was sitting alone. I remember walking around the King Air and thinking how tall the tail was, so much taller than anything I had ever flown before. After a little while, Trevor and I joined up with our assigned training Captain. We headed out to the hangar and up to our King Air. Our Captain completed a very thorough walk around tour of our aircraft. The walk-around included systems discussions including the main door entrance and the air seal system, thinking back to ground school just a week before, I recalled that the main engine bleed air (P3 bleed air) is reduced in pressure in series of manifolds and used by a number of systems, one of which is used to create a door seal that allowed for aircraft pressurization to occur. When the aircraft takes off, a left main gear squat switch opens to remove power from a normally open door seal valve, the seal inflates. A crack in this door seal can cause a very annoying and loud (high-frequency noise) door leak or cabin pressure loss, for this reason, the door seal is inspected each flight for any cracks or concerns.
Thinking even more about ground school, I recalled that the pneumatic system extracts bleed air from the PT6 engines’ fourth stage compressor section (P3 Air) and transfers it to various other systems (i.e. surface de-ice, rudder boost, brake de-ice, bleed air-warning and the above-mentioned door seal). A venturi-ejector in the system creates a vacuum source for the air-driven gyros, pressurization control and the deflation of the deice boots. Yes, there is a lot going on with the pneumatic system on a King Air!
Eventually, we made our way to the #2 engine (a Pratt and Whitney Canada PT6A-42). We opened the engine cowlings on both sides, reviewing the many components of this amazing reverse flow jet engine.
As I can recall, we discussed the importance of checking oil and most importantly checking the oil cap for security after you check or fill the oil. This may seem like not so big of a deal but let’s quickly look a deadly crash of a King Air 100 at CYVR in 2011. The headlines read “Plane’s loose oil cap began fatal chain of events in crash”, The oil cap on the left engine was not tightly latched”
Using a ladder, locate the oil filler hatch on the engine. Open latch, pull up the locking tab and carefully remove the dip stick (using a clean rag to catch any drips).
Check the oil level carefully, observing how many quarts low you are (see your company for oil filing procedures and levels). Overfilling a PT6 with turbine oil is bad news, ensure you are trained before attempting.
Ensure the cap is secure, the tab is down (locked) and you cannot lift the cap if pulled. Ask for another crew member to double check the security for you. Why? See this TSB article below…
Here is a link to a CBC article discussing the Transportation Safety Board of Canada investigation of the crash:
Another area that was discussed in the TSB investigation was training:
“The board found that there is a risk: Pilots will not anticipate aircraft behaviour when using asymmetric thrust near or below unpublished critical speeds and will lose control of the aircraft. And that is precisely what happened in this occurrence.”
As a pilot of advanced aircraft, you must be aware of the risks of flying near Vmc. If you flew with me as a Multi-Engine Flight Instructor, I would have demonstrated simulated single engine flight approaching Vmc. If you can recall from your own training, when operating on a simulated single engine, as you slow the aircraft, approaching Vmc, the aircraft becomes very hard to control, you will have a really hard time handling the aircraft or lose control of the aircraft when you least expect it, short final to your intended runway.
Over the years flying with many Captain’s the one thing that sticks out about the King Air and passenger briefings, is the main cabin door. One Captain put it simply if the passenger can remember the non-intuitive steps to opening the door, they will likely be OK getting out on their own in an emergency. He said that at least one person needs to be shown, and actually open the door to get it to sink into their heads properly. When flying a King Air and you are doing the Passenger briefing – telling them about the unique way of opening of the door – push the button – rotate the handle counter-clockwise, push the door out. This information likely saved the lives of the passengers on the accident King Air 100.
Such a horrible accident to read about, and now you know how important it is to check and double check those oil caps on turboprop engines.