AIRCRAFT ACCIDENT REPORT
- This report is to promote aviation safety and not to establish legal liability.
- The CAA’s report contains padding, repetition, poor English and incompetence. So, in the interest of clarity and readability, I have had to correct and paraphrase extensively.
Type of Aircraft: Piper 34-200T (Aeroplane)
Aircraft Registration: ZS-MTY
Date and Time of Accident: 23/12/2013 1430Z
Type of Operation: Training
Pilot-in-command (instructor) Licence: Airline Pilot
Licence Valid: Yes
Total Hours: 2550 • Total Past 90 Days: 110
Total on Type: 102 • Total on Type Past 90 Days: 20
Pilot 2 (Pilot undergoing conversion)
Gender: Male Age: 52
Licence Type: Private Pilot Licence
Licence valid: Yes
Total Hours 345.2 • Total Past 90 Days: 4.0
Total on Type: 29.2 • Total on Type Past 90 Days: 0.8
Last point of departure: Lanseria International Airport (FALA)
Next point of intended landing: Lanseria International Airport (FALA)
Location of the accident site: Right of runway 07 at FALA
Meteorological Information Temperature: 28°C, Wind: 330°/7kts, Visibility: CAVOK, Dew point: 12°C
Number of people on board: 2
Number of people injured: 0
Number of people killed: 0
A flight instructor and private pilot departed from Lanseria International Airport (FALA) with the intention to complete a conversion onto type flight.
The pilots completed three uneventful circuits for runway 07. During the fourth circuit, the private pilot configured the aircraft for the touch and go landing with full flap and undercarriage extended. The private pilot attempted to flare the aircraft at approximately 20ft above ground level for landing. However, the aircraft ballooned due to excessive back pressure applied to the control column.
The private pilot did not relax the back
pressure to correct for the balloon landing but instead, he increased power on both the engines.
‘A poor mind-set on the part of both instructor and pupil’
The aircraft’s airspeed decayed, and the aircraft began to yaw to the right. The flight instructor took control of the aircraft and tried to regain directional control and to recover from the stall. The instructor could not regain directional control, so he reduced power to both engines to idle, and the aircraft crash landed to the right of runway 07. It skidded for approximately 90 meters before coming to rest.
The air traffic controller (ATC) on duty activated the crash alarm and aerodrome rescue and fire-fighting (ARFF) were dispatched to the crash site. The pilots evacuated the aircraft unassisted and without injury. The aircraft sustained substantial damage.
Video footage of the accident sequence leading up to impact was obtained from Apron management at Lanseria Airport. The footage was used to verify the sequence of events following impact.
The aircraft’s airspeed was allowed to decay during a balloon landing recovery, which resulted in a stall and subsequent loss of directional control.
Damage to Aircraft
The aircraft sustained substantial damage to the fuselage, undercarriage, wings, engines and propellers.
Weight and Balance
Basic Empty Weight 3017
Pilot and Passenger 410
Fuel on board 490
Take-off weight 3917lbs
Note: The maximum take-off weight for this aircraft is 4570lbs. The aircraft was within the take-off weight limitation.
Wreckage and Impact Information
The aircraft made contact with the ground and came to rest approximately 90 meters from the initial impact point in a southerly direction. It sustained substantial damage to the propeller, undercarriage, wings and fuselage. The main undercarriage separated on impact.
The damage to the propellers indicated a low power setting at impact and neither of the propellers was feathered. Following the accident the pilots indicated that the mixtures were fully rich.
Tests and Research
The following information has been extracted from the Pilot’s Operating Handbook: Stall speed with flap extended: 61kts.
- To recover from stall, reduce the angle of attack by moving the control column centrally forward until the buffet or stall warning stops.
- Once the wings are unstalled, buffeting ceases, the airspeed increases and the aeroplane can be eased out of the slight dive back into normal flight.
- The height loss will be of the order of 200 feet.
- Power can be added to regain or maintain height, otherwise flying speed should be maintained in a glide.
- Height loss during stall can be minimised with power.
- Adding power is not required to recover from the stall, however height loss will be minimised if full power is applied as back pressure is released and the nose is lowered.
- Recovery can be achieved with a height loss of less than 50 feet.
The information below was extracted from the Air Pilot’s Manual, Volume 1:
A balloon can be caused by:
- Too much back pressure on the control column; and/or
- too high an airspeed; and/or
- a gust of wind.
To correct for a small balloon:
- Relax some of the back pressure on the control column.
- Allow the aeroplane to commence settling (sinking) again.
- When approaching the hold off height, continue the backward movement of the control column; and
- complete the landing normally.
Stalling occurs when the critical angle of attack of an aircraft is exceeded. A speed is used as a reference because light aircraft do not have critical angle of attack indicators.
Warnings of an impending stall include:
- a reducing airspeed;
- operation of a pre-stall warning (warning horn, buzzer or light);
- the onset of buffet (a vibration felt on the control stick); and/or
- high nose attitude.
The aircraft’s right engine and turbo charger were subjected to a teardown inspection following the accident to eliminate the possibility that an engine failure of the right engine had occurred, resulting in an asymmetric scenario. No abnormalities were found and this duly eliminated the possibility of any asymmetric scenario.
This is interesting because there weren’t really any warning signs. So we have a nice day with light winds, a reasonably experienced and current instructor, a lightly loaded, apparently serviceable aeroplane, and a good, big, international airport. What can go wrong?
To me it looks like a poor mind-set on the part of both instructor and pupil. Perhaps caused by it being towards the end of a long hot day. I will say more about that shortly.
But I am also interested in the poor wording used in the report – both CAA’s and the words quoted from the Air Pilot’s Manual (Vol.1). Words that I see being increasingly used by instructors and sanctioned by CAA.
Some non-instructors may feel that words are unlikely to cause accidents. Wrong. Words are extremely important when instructing. Words can be misleading and sometimes plain dangerous.
‘In summary: Pressure means nothing’
My current hate is the word ‘pressure’ when applied to control inputs. Putting pressure on a control does nothing – it’s necessary to move the control before anything happens. All controls suffer from what engineers call stiction which is defined as the static friction that needs to be overcome to enable relative motion of stationary objects in contact. The term is a portmanteau of the words static and friction, perhaps also influenced by the verb stick.
This means you are not going to get more power by putting forward pressure on the throttles – you have to move the damn things to overcome the stiction caused by the throttle friction nut. This is an extreme example, but ALL controls have some degree of natural stiction and some have it designed into them.
A Cherokee’s flap lever won’t move if you put pressure on it – you have to deliberately use some muscle to lower the flap. Even the magneto switch has built in stiction – you can’t have it flopping from one mag to the other in turbulence. Your instructor doesn’t tell you to put pressure on the flap lever or the ignition switch – he wants you to move it. And the same applies to the flying controls.
Stiction is what makes it necessary for you to tap the altimeter (and a barometer) to get a proper reading. Out of interest, in the previous generation of Boeings you could just hear a very light, but continuous, tapping noise in the cockpit. This was caused by minute hammers that tapped the altimeters all the time, to overcome stiction in the instruments. With piston engine aircraft the vibration is enough to do the job.
So when the otherwise excellent Air Pilot’s Manual suggests that you enter or recover from stalls by applying, or relaxing, back pressure on the control column, they are tip-toeing round the truth. And they know it – because the next moment they tell you to ‘continue backward movement’ of the control column.
The POH uses the correct wording when it says, to recover from stall reduce the angle of attack by moving the control column centrally forward until the buffet or stall warning stops.
In summary: pressure means nothing – all the controls need to MOVE before anything happens.
All this is getting me wound up about instructors and training manuals using the correct words, so while I am on a roll let’s take it a bit further. Where possible, don’t tell pupils what to do with the stick – it’s much better to tell them what to do with the aeroplane. The Air Pilot’s Manual, quoted in this report says When approaching the hold-off height, continue the backward movement of the control column.
That’s extremely bad advice. Do they really want you to continue moving the stick back even if you balloon? Of course not. But maybe that’s exactly what this pilot did.
If you are teaching someone to drive a car you don’t tell them what to do with the steering wheel when they are going round a corner – you tell them what to do with the car. “Keep it on our side of the road,” or whatever.
Okay having dealt with bad instructional techniques let’s move on to the fairly simple matter of what really caused this accident. A few things went wrong, all pretty much at the same time:
- The pupil rounded out too high, or possibly ballooned.
- He corrected by adding partial power instead of lowering the nose immediately.
- With turbocharged twins the power is unlikely to increase equally on both engines at the same time – this probably caused the yaw, or roll to the right.
- The instructor was fast asleep – he left it too late to intervene. Possibly he was tired after a long hot day, as I suggested earlier, but takeoffs and landings, particularly in a twin, demand one’s full attention.
- The fact that the pupil had nearly 30 hours on type probably gave the instructor a false sense of confidence in him.
- Also, a pupil who hasn’t finished the conversion in about ten hours has to be suspect.
- I didn’t witness the accident, and the report doesn’t give enough information, but it seems the event was very badly handled by whoever was at the controls. They failed to maintain flying speed and directional control of a serviceable aeroplane.
- I suspect they were not mentally prepared for a go-around. This would never have happened if they had been.
- At 650 lbs below gross weight the aeroplane was easily capable of doing a go-around even if one engine had failed – which was not the case.
Take Home Stuff
- Everyone needs to be wide awake even during the most straight forward takeoffs and landings.
- When landings go wrong they demand immediate and positive action. This is not a time for half measures or a wait-and-see attitude.
- On final approach one should always be prepared for a go-around – almost expect it.
- Be aware that long hours and hot days are going to rob you of your normal spark.
- Instructors beware – the more hours and experience a pupe has, the less you should trust them. My worst scares have always been with seemingly competent people. With a low hour pupe you are prepared and ready for silliness, but there’s always a “I don’t believe this is happening” moment when an experienced pilot does something goofy.