The Piper Cherokee PA 28 Series

I love these aeroplanes because they are easy to maintain, whilst parts are reasonably priced and the aircraft are very easy to repair if damaged.

Oddly enough the order in which they were produced is not as stated below. One would imagine that the 140 was first to be produced when in fact it was the 160. According to the Type Certificate the PA28-160 was first off the line being approved in October 1960. Next was the PA28-150 in June 1961, the PA28-180 in August 1962, the PA28 235 in July 1963 and then the PA28 -140 in June 1965.

It is surprising how many people think that a PA28 -140 is 140 HP and a PA 28-150 is 150 HP and so on. In fact, the 140 and 150 have the same engine option, the Lycoming 0-320 E2A producing 150 HP. The PA28 – 160 is 160 HP and the PA28 180 is 180 HP and so on. It is rather confusing that the 140 is not 140 HP as is often believed.

Over the years there have been many changes to these aircraft in terms of upgrades in appearance, performance, cabin ergonomics, cabin stretches, additional windows, increased wingspan and design of wing, engine exhaust and cowling changes.

However, also importantly by safety improvements often introduced by Service Bulletins or Service Letters. Sometimes there is an Airworthiness Directive (AD) on the same subject. These normally require a repetitive inspection based on hours flown or calendar time with, in some cases, the option to upgrade to a new improved part which then alleviates the repetitive inspection.

SOME EXAMPLES BELOW

Main gear torque links and bolts (several service letters, bulletins and ADs)

All in all, there have been three changes to the torque links and greaser bolts to make them safer.

Aileron hinge doublers (SL 581)

Often ignored, but important to check because they do crack. Service letter advises on a kit that can be installed to alleviate the repetitive 100-hour inspection.This also provides material thickness so that one can identify if the upgraded part has been installed.

Ammeter modification (SB811A)

Required on certain serial numbers to preclude potential cockpit fire. This was mandatory back in 1986 and requires a new type of ammeter.

Stabilator balance weight tube (SB 327)

Early models have a thin walled tube and require a 200-hour repetitive crack inspection. An upgrade was offered by this Bulletin to alleviate the repetitive inspection. This is easy to identify visually if it has been done.

These are just a few examples that have made the aircraft safer. Some of these publications also apply to PA 32 aircraft and in some cases the PA 28R and PA32R. Unfortunately, these models also suffer from corrosion problems due to the use of dissimilar metals, where steel fittings have been riveted to aluminium.There have also unfortunately been some wing failures due to fatigue and/or corrosion. As an owner it is important that one makes sure that the AMO concerned does the inspections and rectifies the issues. Some of this becomes quite pricey, especially if the wing spar is found defective. Owners need to be aware that there is an inspection required on wing spar bolt holes depending on hours flown and conditions of the flights. Please check with your AMO and for peace of mind get it done.

FAA proposes changes to Cherokee wing spar AD

The FAA is proposing fine tuning a massive proposed (AD) on Piper Cherokee wing spars and removing more than a third of the aircraft originally covered. It has also added a few models, but the net reduction is 8,800 airframes from the original list of more than 20,000. The five aircraft removed from the list are the PA28140, PA28-150, PA28-160, PA28-161 and PA28-180. The models added include the PA32R-300, PA32RT-300 and PA32RT-300T. The proposed AD was sparked by the crash of an Embry-Riddle Piper Arrow PA28R-201B, which lost a wing on a commercial check ride in 2018, killing the applicant and his examiner.

The original Notice of Proposed Rulemaking (NPRM) used the broad-brush approach and covered Cherokees with the same wing design of the crash aircraft, notably an area of the main spar subject to cracking that is not visible without tearing apart the wing. The Supplemental Notice of Proposed Rulemaking (SNPRM) applies a risk-based approach that considers service history and wing loading. The applicability list includes models that have similar or greater wing loading than the crash airplane and the service records are also reviewed (by counting the number of 100-hour inspections) to identify higher-risk aircraft that have been used, for example, as training aircraft.

Aircraft on the revised list with 5,000 hours or more, those that have missing or incomplete service records and those that have had spars replaced with used spars will get their records reviewed to determine whether the type of service the aircraft has seen warrants the complex inspection, which includes eddy current testing of the hidden spar area. Only aircraft with 5,000 or more ‘factored service hours,’ hours which include high-cycle numbers and other hard use, will be inspected so that means that many aircraft with much higher time will not need the inspection.

Otherwise the Piper Cherokee PA 28 is a great aircraft. Perhaps not as popular as a Cessna 172 which is preferred by flight schools, but in my opinion is actually the perfect flight school plane as it seems to tolerate bad landings better than the 172 and the Cherokee costs a lot less to repair if the nose gear is damaged by a bad landing.

About Tom Willows

Tom Willows has been in aircraft maintenance for over 46 years. Having spent five years in the then Rhodesian Air Force, he sampled various other sectors of the industry to find his niche. With time spent at a civilian contractor to the Air Force, time with airliners and time with helicopters, in 1988 he eventually settled in his niche sector, being light piston engine aircraft. Since then Tom has dedicated himself to this sector and is committed to full product

knowledge to the aircraft on which he is he is licensed.

Tom is a self-professed petrol head and particularly enjoys radial

engines and other vintage aircraft and engines.

Tom’s company Aircraft Unlimited is based at Rand Airport

Cell 082 366 7262 or e-mail: tom@aircraftunlimited.net