Epic E1000 Gets the GFC 700

Need To Breath

ByRyne Bergren March 28, 2019April 30, 2019

I got a call today from a friend asking me about oxygen requirements.  That got my brain pondering about the different items the FAA would like all pilots to know. I did a little refreshing and found several other tidbits directly from the FAA that I thought worth sharing. No matter what you’re flying, I think these apply to all of us. 

First off, what are our general oxygen requirements? If you jump on over to the FAR’s and take a look at 91.211 you’ll see: 

1. At cabin pressure altitudes above 12,500ft MSL to 14,000ft MSL, pilots
required to use oxygen unless the segment is less than 30 minutes of flight.

2. At cabin pressure altitudes above 14,000ft MSL, the crew is required to use
oxygen.

3. At cabin pressure altitudes above 15,000ft MSL, each occupant must be
provided the use of oxygen. This doesn’t necessarily mean they have to use it.

Things get a little more in depth when you get to pressurized aircraft.

These requirements are also listed in 91.211: 

1. If you’re flying above Flight Level 250, a 10 minute supply of oxygen is
required for each person onboard.

2. If you’re flying above Flight Level 350-410, and one pilot leaves their seat, the other pilot will be required to wear an oxygen mask, unless both seats are equipped with quick-donning oxygen masks.

There are three basic components to any oxygen system in an aircraft:  the storage system, the delivery system, and the mask or cannula. First, there are several types of storage systems. 

Gaseous aviators breathing oxygen is the first. This is the standard green tank that everyone is familiar with. There are two types of tanks. Either the high- pressure with 1800-2200 psi or the low pressure tank with 400-450 psi. The major issue with these and General Aviation aircraft is weight. Some of these tanks can get bulky and heavy and therefore don’t work for everyone. 

Liquid aviators breathing oxygen or LOX is another form of storage. The major advantage of LOX is that it has a 900 to 1 expansion ratio, meaning that 1 liter of liquid oxygen can be expanded into 900 gaseous liters of Aviators Breathing Oxygen. The disadvantages of LOX are they are extremely volatile and have to be stored at -197F. If it comes in contact with exposed skin, severe frost bite can occur. 

Sodium chlorate candles or oxygen generators have a weight advantage like LOX. They’re essentially a canister that when activated mix sodium chloride and iron powder and produce oxygen. They general have a 600 to 1 expansion ratio, which goes back to the weight savings. However, once these are started they are very hard to stop. Another disadvantage is these devices produce a fair amount of heat, so proper precautions need to be taken. 

Next are the delivery systems. The main systems are Continuous Flow, Diluter Demand, and Pressure Demand. Continuous Flow, is exactly as it sounds. The oxygen is allowed to flow continuously from the tank to the user. The benefits of continuous flow are you don’t need a complicated mask or regulator. The downside to this system is since it continuously pumps oxygen, you’re wasting oxygen when you exhale. Most of continuous flow systems are used on aircraft that generally fly below 28,000 feet. 

Diluter Demand was designed to fix the negative of the Continuous Flow systems. Diluter Demand only sends oxygen to the user when the user inhales. The system also allows cabin air to be introduced in, sending the perfect mixture of oxygen to the user when needed. These systems are very efficient and generally tend to be used up to 40,000 feet. 

Pressure Demand is designed to essentially “over inflate” the users lungs. This will basically pressurize the the users lugs and allow the user to fly above 40,000 feet. This is needed at flights above FL400 because 100% oxygen without positive pressure will not suffice. 

The final portion of the oxygen system is the mask or cannula. Nasal cannulas generally are more comfortable and are regulated to 18,000 feet service altitude. Masks come in a couple different variants. From re-breathers to quick-donning, most masks accomplish the same task with a few small differences. Quick-donning must be able to be put on within five seconds and are rated up to FL400. 

Since that was a lot of information, what does all of it mean to you? Most fair weather flyers will never run into any of this. However, the high performance owner/operator will run into oxygen use situations a fair amount. Taking the family up to Colorado on a ski trip, jumping up to 12,500 feet to get above some weather, or flying above 5,000 feet at night on a long xc are all situations where you may want to have oxygen on board. 

If you are planning on doing any of this type of flying or are currently doing these types of flights, training is a must. If you’ve never been in an altitude chamber, I would highly recommend it. In college, I went with a group to Oklahoma City to the FAA’s headquarters where they hold a class on Hypoxia and High Altitude flying. It’s very informative to be in the chamber as it simulates being oxygen deprived. You get to see how you’ll react and what kind of symptoms you’ll have when in a loss of oxygen situation. Each person has different symptoms, so it’s important to see how you will react.

It’s also good to fly with an experienced instructor. Finding an instructor who will allow you to learn in a safe environment is worth its weight in gold. 

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Ryne Bergren is currently a First Officer with Mesa Airlines in the CRJ 900. Ryne has experience in many different areas of aviation, from corporate to airlines to teaching to ferrying across the Atlantic Ocean. His passion is for all things that travel across the big blue sky.

Contact Approaches

ByHank Gibson June 20, 2020June 20, 2020

Almost all IFR pilots are familiar with visual approaches and what the requirements are in order to fly a visual approach. As a refresher, the Instrument Procedures Handbook defines a Visual Approach as “an ATC authorization for an aircraft on an IFR flight plan to proceed visually to the airport of intended landing; it is not an [Instrument Approach Procedure]” (page 4-56).

For ATC to issue a Visual Approach, the pilot must have the airport or the traffic to follow in sight. Once the pilot reports the airport or the traffic in sight, ATC can clear the aircraft for a visual approach.

A limiting factor for a visual approach is ATC’s Minimum Vectoring Altitude. “This altitude, based on terrain and obstruction clearance, provides controllers with minimum altitudes to vector aircraft in and around a particular location” (Instrument Procedures Handbook page 1-42). ATC has to restrict aircraft to these MVAs, which can sometimes be quite high due to terrain or obstacles in the vicinity of the airport.

Every pilot has been in a situation with a high MVA that ATC can’t get them below, but it’s solidly MVFR or VFR at the destination airport. The MVA keeps the pilot in the clouds, so a visual approach isn’t possible since the pilot can’t see the airport or the traffic to follow. This can lead to extra time to go out and fly an approach.

Enter a Contact Approach. A Contact Approach is different then a Visual Approach. “The main differences between a visual approach and a contact approach are: a pilot must request a contact approach, while a visual approach may be assigned by ATC or requested by the pilot; and a contact approach may be approved with 1sm visibility if the flight can remain clear of clouds, while a visual approach requires the pilot to have the airport in sight, or a preceding aircraft to be followed, and the ceiling must be at least 1,000 feet AGL with at least 3sm visibility” [Instrument Procedures Handbook page 4-57].

Here’s the simplified explanation: A pilot does not have to have the airport in sight to request a contact approach. All that is required is for the airport to be reporting at least 1sm visibility and for the pilot to remain clear of clouds.

When would this be helpful for an IFR pilot? Good question. Here’s a scenario.

Pilot Smalls is about 20 minutes from his destination, which is an uncontrolled airport with only one approach to runway 17. He is approaching from the south and the initial approach fix for the approach to 17 is about 15 miles north of the airport. The airport is under Center control. When he has arrived at this destination in the past, Center usually could only vector him down to 4,000 AGL. He is very familiar with this airport and the surrounding area as he comes to this destination at least 2-3 times a month for business.

Pilot Smalls listens to the AWOS, which is reporting a 2500 foot scattered layer and 10 miles visibility. He knows it is right traffic for 17 since there is a 2,000 foot antenna on the east side of the field. There is some hilly terrain around, but all the terrain is well below pattern altitude and doesn’t cause a safety issue.

Looking out at the clouds, Pilot Smalls observes that the cloud layer is scattered to broken, but more scattered on the west side of the airport, with several large openings that he can see the ground through. Center asks for his approach request and Pilot Smalls requests a visual approach. Center gives him a descent to 4,000 AGL, their MVA for the area. They tell him to report the airport in sight for the visual approach.

At 4,000 AGL, Pilot Smalls is going through the scattered layer of clouds, but can see the ground in between the clouds and deems he has room to maneuver safely between the clouds and stay clear of them. He can’t see the airport, so a visual approach seems unlikely. He can’t cancel IFR because then he would have to keep the VFR cloud clearance and visibility requirements in Class E airspace (1,000 feet above, 500 below and 2sm horizontally), which isn’t possible in this case.

5 miles from the airport, ATC states, “N12345, I’m going to have to send you out for the approach since you don’t have the airport in sight.” Pilot Smalls then requests a Contact Approach. ATC clears him for the Contact Approach to his destination, so Pilot Smalls descends through a break in the clouds, remaining clear of clouds, until he gets below the base of the ceiling. He maneuvers onto the right downwind, lands and cancels IFR.

Contact approaches can be useful at controlled and uncontrolled airports. The first time you request one, do so with a higher ceiling and some room to maneuver to keep your safety margins. After you’ve done a few, you can determine what your personal minimums are for a Contact Approach.

I would not recommend doing a Contact Approach at an airport you are unfamiliar with. It’s vital to know what obstacles are around since on a Contact Approach, the pilot is now responsible for traffic avoidance and terrain avoidance, whereas on a visual approach, ATC resumes that responsibility.

For more reading on Contact Approaches and another good scenario, check out Bold Method’s article on Contact Approaches.