Another CAIR report. This time an Aztec
CAIR Report – Aztec: Around 1995 era
The purpose of the flight was to endorse a pilot on type. The author arrived at the airport to find that the pilot under instruction had been verbally briefed by the company chief pilot that there were problems with the cockpit door which was hard to close and which had previously opened in flight. He said that if the door came open on final, the pilot should increase the approach speed by five knots.
This statement indicated that the door defect was a known event on this particular aircraft. The chief pilot further advised of a faulty autopilot pitch control channel and that it should be only used in two axis. He also indicated that the EGT gauge for both engines was inoperative.
The maintenance release showed that some 65 hours had been flown since the last 100 hourly inspection. There were no recorded defects endorsed in the maintenance release at the time of our flight. However, a company designed flight record sheet that was attached to the maintenance release had an annotation that that the cockpit door had opened twice during one flight. The last three flights shown in the flight record sheet had not been recorded in the maintenance release.
On attending the aircraft the door was found to be ill-fitting and it took several attempts to secure it from inside the cockpit. Abnormal force was needed to push its handle over-centre. As with other types of aircraft, once locked from inside it is not designed to be opened from the outside, thus making it impossible for rescue purposes from the outside.
This Aztec was fitted with only one hydraulic pump with which to operate the landing gear and flaps. This pump was on the left engine. In event of a failure of the left engine, the pilot would operate an emergency hydraulic hand-pump to operate the landing gear and flaps. Thus, besides securing the dead engine, the pilot would be forced to fly with one hand, while withdrawing the hand-pump from its socket with the other hand, before pumping the gear into the wheel wheels. A vision of the proverbial one arm paper-hanger springs to mind.
In this case the single engine rate of climb would be negative and a crash landing ahead inevitable, unless the gear was up at the time of engine failure. Despite this problem, at the time of this report the Aztec was still considered “safe” for charter flights. Some Aztecs have a second engine driven pump installed on the right engine at owner’s option.
After the instructional flight the following defects were recorded in the clean maintenance release:
1. The stall warning system failed to operate during stall recovery demonstrations.
2. The landing gear warning horn failed to operate and the red gear warning light in the gear lever failed to illuminate with gear up and throttles retarded.
3. Control column movement fore and aft caused squealing noises due lack of lubrication. This could be clearly heard during the landing hold off and when checking freedom of movement.
4. The Turn Coordinator was abnormally noisy during gyro run up.
5. Both CHT gauges appeared either unserviceable or unusually under-reading. Neither needle left the bottom (cold) stop although the right CHT needle did flicker higher a couple of times. As I had not flown this particular aircraft before and the OAT was only 10C, I accepted these low readings during run-up, but once airborne there was no discernible increase above the low stop.
6. Both EGT gauges inoperative
.7. The mandatory second artificial horizon (AH) was installed in the bottom far right hand corner of the copilot’s instrument panel and well outside the normal scan from the LH seat. The gross parallax error when viewed from the LH seat would negate the purpose of the second AH and in any case may lead to vertigo as the LH seat pilot leaned way over to his right to see the second AH. This is a well known problem with installation of some second AH’s to satisfy an airworthiness requirement.
It would be dangerous at night if the pilot was faced with a failed AH and was forced to rely on the second instrument well outside his scan. With a passenger in the RH seat, the second AH was not visible to the occupant of the LH seat.
8. The left engine manifold pressure needle (dual needles in a single gauge) frequently failed to respond to power changes until a differential of at least 6 inches of manifold pressure occurred. The needle would then move sluggishly to take up an appropriate reading. This fault showed throughout the flight whenever the throttles were repositioned.
9. The radio switch panel displayed a switch marked No 2 VHF.Nav receiver and another marked as No 2 VHF transmitter. In fact there was only one VHF and one VHF-Nav. These switches should be labelled as inoperative.
10. The feedback on VHF transmissions was scratchy and practically unreadable.
11. On two ILS approaches, while at 3 miles from the runway, the localiser needle showed one dot off centre with the aircraft visually aligned on the runway centre line. On one approach there was a rapid oscillation of the localiser needle on 3 miles final. Oscillation was less on the second ILS approach.
12. The autopilot over-controlled in roll and a severe pitch/bunt occurred when the pitch channel was engaged. No further attempts were made to experiment with the auto-pilot.
13. Attached to the pilot’s control wheel were two unidentified switches. One had the word ‘Winchester Electronics Incorporated” etched on the assembly. This was a press-to-transmit type switch and had it’s button missing, leaving a very nasty sharp threaded point for the pilot to push. The other switch was concealed under the wheel and not readily noticeable until inadvertently felt. It was a black toggle switch, spring loaded to centre, and operable in either direction. There was no labeling to indicate the purpose of either switch and no Flight Manual annotation.
14. With both mixture controls full forward, their position was at least two inches from the top edge of the quadrant, and looked as though they were actually in a mid-lean position. This may be an Aztec characteristic?
15. During run-up, the right pitch control was abnormally stiff to operate throughout the full range from Fine to Feather.
16. The parking brake was useless. As soon as moderate power was applied to any engine for run-up, the aircraft would move forward and veer left.
17. The right brake was weak during landing. Equal foot pressure on both pedals produced a marked turn to the left.
18. The altimeter on the copilot’s side showed 120 ft less than the pilot’s altimeter for same QNH. This was on the ground. There was an 80 ft difference when airborne. The right altimeter was outside IFR limits.
19. On two ILS approaches, the marker beacon lights and audio for the OM and MM failed to operate. The light globes also failed to operate on press to test.
20. The emergency exit window (passenger) is not labelled in any form. There is a single red handle beneath the window. This handle faces forward, but is unmarked. It would be easy for a passenger to inadvertently knock the handle with an elbow.
21. At 1100 rpm, the right engine manifold gauge needle oscillates rapidly over a 150 rpm range.
22. The pilot’s overhead vent control has an exposed metal shaft. The plastic round button is missing.
23. The internal dim/bright lights on the ADF digital control panel appear to be stuck in the dim position.
24. There is a radio rheostat switch labelled “Radio Light”. The switch may be disconnected or inoperative, as it does not appear to illuminate anything. If so, it should be labelled Inoperative.
25. The flap indicator needle indicates slight flap extended, although the flaps are confirmed visually up.
26. Most circuit breakers are underneath the left instrument panel out of sight of the pilot in the normal seated position. A portion of the decal serving these circuit breakers has been obliterated due wear and it takes time to read exactly what services are covered. Impossible at night.
27. A fire extinguisher is installed under the copilot’s seat. A label reveals that the last inspection was in 1986.
28. There is no POH in the aircraft. The Flight Manual did not have a copy of the C of R inside.
29. The ASI has no markings for Vmca, or blue line speed.
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Comments. In view of the inoperative stall warning and gear unsafe warning, the author endorsed the maintenance release as aircraft un-airworthy. This Aztec is used for charter flying by the operator. Signatures on the maintenance release indicate that at least 8 pilots have flown this aircraft since the maintenance release was issued.
It is difficult to believe that there were no defects apparently discovered during the 60 hours of flying until I flew it. The chief pilot was clearly aware of some of the defects because he cautioned the pilot under conversion prior to our flight.
Many of the defects must have been current during the last 100 hourly inspection, but the maintenance organization have appeared to missed them – or more likely deliberately ignored their presence. I understand that the operator has recently undergone routine surveillance by CASA inspectors. Presumably this would have included an inspection of airworthiness aspects of this aircraft. If so, the inspectors concerned perhaps lacked their usual vigour?
A short flight test would have revealed the in-flight defects such as those listed in this report. After all, cars are subject to a short road test to renew some roadworthy issues, so perhaps old aircraft should be required to undergo the same appropriate airworthiness flight tests as part of charter approval for the type.
If nothing else, there should be an airworthiness investigation on the positioning of the second AH which is required for IFR charter. I have seen this problem on many GA types, although this particular Aztec was the worst example. There is little point in having flight instrument redundancy if the pilot faces serious aircraft handling problems when forced to fall back on the spare AH which may be outside his normal scan. The Monarch Airlines Chieftain accident inquiry revealed a similar problem in instrumentation.
Airworthiness authorities are rightly concerned with correctness of paper work during routine operator surveillance. From my experience there is a clear need for inspectors to crawl around a few cockpits. Many of the defects that I have listed on this Aztec should have been readily apparent to a diligent flying operations or airworthiness inspector who took time to open the door – that being the very first defect.
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