The latest in a series of articles by the FAA on preventing loss of control accidents deals with best practices to calculate and predict aircraft performance and on operating within established aircraft limitations.
What is Loss of Control?
A Loss of Control (LOC) accident involves an unintended departure of an aircraft from controlled flight.
LOC can happen because the aircraft enters a flight regime that is outside its normal flight envelope and may quickly develop into a stall or spin. It can introduce an element of surprise for the pilot.
Contributing factors may include: Poor judgment/aeronautical decision making, failure to recognize an aerodynamic stall or spin and execute corrective action, intentional regulatory non-compliance, low pilot time in aircraft make and model, lack of piloting ability, failure to maintain airspeed, failure to follow procedure, pilot inexperience and proficiency, or the use of over-the-counter drugs that impact pilot performance.
Investigations of General Aviation Loss of Control accidents often cite failure to predict aircraft performance, and flight operations conducted outside of the aircraft’s established limitations.
Pilots can start by asking themselves:
- How much can I haul?
- How far can I go?
- How much fuel do I need?
This includes weight of passengers, fuel and cargo.
It also includes departure and arrival runway lengths, obstructions and expected density altitude.
How do I plan?
Start with your crew and passengers, and then add cargo. If these items alone exceed your plane’s capability, you’ll either have to make several trips, or get a bigger aircraft.
You will also need to calculate how much fuel you can take, and whether you’ll have enough to get to your destination, plus an alternative.
Finally, you’ll need to consider your departure and arrival runway lengths, obstructions and expected density altitude.
Be conservative when calculating your plane’s performance, and consider adding a safety factor. Some pilots add 50% to their takeoff and landing calculations for safety.
What’s the greatest variable?
The pilot is the greatest variable in this plan. All of your calculations will not mean much if you cannot duplicate them in flight.
That’s why it’s important to document your performance capability at least once a year, with a CFI on board. Fly at a typical mission weight, and try to duplicate or simulate mission density altitudes. That way, you’ll know what you and your aircraft can do.
Establish a Baseline
In order to know what performance you and your plane are capable of, you’ll need to establish a baseline. Think of this baseline as a reference point that relates to your performance, and that of your aircraft, under a given set of circumstances on a given day.
High density altitudes and human factors, such as fatigue, will result in performance below the baseline. Proficiency training and lighter loading will likely result in performance that exceeds the baseline.
The key point is that for any given flight, your baseline will determine what you need to know about how your aircraft will perform.
What are Limitations?
Limitations are derived from Physical Laws, including:
- Weight and Center of Gravity,
- Speed Limitations,
- Aerodynamic Loading for Normal, Utility and Aerobatic certification categories.
Many limitations are easy to exceed, so you must be careful to operate your aircraft within its limitations at all times.
Tips for pilots
There is no substitute for careful attention to your aircraft’s performance and limitations.
Document your performance capability at least annually.
Pay careful attention to weight and balance, conditions at your departure and arrival airports, and your expected density altitude.
Know your aircraft’s limitations under all conditions, and never exceed them.
Did you know?
- Last year, 384 people died in 238 general aviation accidents.
- Loss of Control is the number one cause of these accidents.
- Loss of Control happens in all phases of flight. It can happen anywhere and at any time.
- There is one fatal accident involving LOC every four days.
The Aircraft Weight and Balance Handbook (Chapter 6, 7 and 8, Appendix A) (FAA-H-8083-1A), has several helpful charts and examples:
The Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25A) – (Chapter 8), will help you establish your performance checklist
The FAASafety.gov website has Notices, FAAST Blasts, online courses, webinars and more on key general aviation safety topics.
Check out the 2016 GA Safety Enhancements (SEs) fact sheets on the main FAA Safety Briefing website, including Flight Risk Assessment Tools.
Take time to read the May/June 2015 edition of FAA Safety Briefing dedicated to Aircraft Performance.